Zipping into Risky Territory


Zip line collisions. What causes them, and how do we reduce the exposure to claims and liabilities arising from them? In an earlier article (“People, Places, and Things,” Summer 2019), we examined several possible liability exposures. Here, we focus on zip line clients’ collisions with people and things. Operators, insurers, and attorneys all tell us that these generate the greatest number of liability claims in our industry. 

Collisions and the law. Collisions, as we have noted before, are of many types and have many causes. A zip line rider may run into another person on the line. They may encounter objects, including a tree limb or piece of equipment. The rider may collide with the receiving platform and staff. These collisions can cause serious injuries, claims, and legal liability. 

Other than their frequency, why do these collisions deserve special attention as we consider the safety of our visitors and our exposure to claims?

First, collisions are obvious. Managers and lawyers may argue about contributing causes, but there is nothing subtle about a zip line rider running into someone or something (often in the presence of witnesses).

Second, a zip line rider is, relative to participants in other sports and recreation activities, passive. They are at the mercy of the people, places, and things associated with the zip line. There is a reason we refer to them often as “riders.” This passivity can be a significant factor in determining the duty of care owed to them, as described later.

Finally, a collision can result from a veritable suite of causes: defects in terrain, design, construction, and equipment; errors in staff training and supervision; management’s failure to react to prior events, including near misses; irregularity or incompleteness of inspections, and failure to comply with recommendations; and the violation of local laws and ordinances, industry standards, and prevailing practices.

Claims arising from collisions generally fall into two categories: breach of contract, and negligence. 

Breach of contract. A claim of contract breach asserts that a promise (written or oral) has been broken. A claim for breach of contract may address, and find fault with, any of the aforementioned services: the design and construction (or repair) of the course, equipment, training, and inspection. Did service providers do as they promised?

The agreement between the site and the visitor, sometimes referred to as the visitor agreement, is a contract. Violation of that agreement, including its representations (“our activities are safe”, or “I have no medical condition that would cause me to be a danger to myself or to others”), can produce claims and liabilities. 

Negligence. Most often, however, a party injured in a collision will claim negligence. Negligence is the failure to protect another, to whom a duty of care is owed, from unreasonable risks of harm. A claim of negligence may be directed against the operator of the course, the owner of the site, and any prior service providers who may have contributed to the claimed loss.

At trial, the judge or jury will be asked to determine if the party accused of negligence (the defendant) acted as a reasonable party would have acted under the same or similar circumstances. The judge or jury will typically rely on industry experts in making this determination and often must weigh conflicting advice.

Factors unfavorable to operators. What might suggest a defendant was negligent? The violation of applicable laws and ordinances, standards, and prevailing practices constitutes at least some evidence of negligence. An organization’s history, including employee records, may reveal incompetence and improper practices. A court may consider as evidence anything that adds to an argument that the accused “player”—operator, owner, etc.—did not act reasonably in the circumstances before the court.

The passivity of the zip line rider is an important consideration, too. The rider is placed in a harness, clipped to a cable, and released, relying on gravity, good design, construction, equipment, and a trained staff to “land” safely. If she has responsibilities for slowing her approach, or braking, or raising her feet, she relies on instructions received “up top” or instructions (which may turn to anxious shouts) from the receiving staff. Following instructions should insulate her from claims that she contributed to the accident, i.e., that she was, herself, negligent.

The courts are attentive to the unique duties of landowners, which require that the premises (the course and related terrain) be as safe as they appear to be. In addition, special laws govern liability for products whose design or manufacture might be defective.

Defenses. There are defenses to a claim of negligence, of course, some of which may be set out in the agreement with the visitor—or exist as a matter of state law, independent of any agreement.

These defenses include an assumption of the loss-causing risk (“I understand there might be close personal contact in harness fitting,” for example). There is no duty to protect a participant from an inherent risk of an activity—a risk that is so integral to the activity that, without it, the activity would lose its basic character (anxiety regarding heights, for example). And importantly, a participant may waive or release, in advance, claims arising from the activity (including, in all but a few states, the negligence of a released party but not its gross negligence or recklessness). 

Contribution and indemnity. Liability may be shifted among or between the parties who may have contributed to the event or circumstance before the court. Builders and other service providers, for example, may seek indemnity (protection from liability, a defense of claims, and costs) from the owner or operator of the course for claims that do not arise directly from their services.

The avoidance or shifting of liability is most successful if the parties agree to it in writing as part of the contract for services. The protection sought can be quite broad (“any accident or loss occurring after completion of the service”) or limited (“all claims except those which arise solely from a defect in the performance of the service provider”).

In certain indemnity situations, a judge or jury may allocate responsibility, and payment of the claim, between or among the parties implicated. The party bringing the suit may be found to have contributed to the loss, too, and its recovery reduced accordingly.

How does all this play out in the real world? A recent Colorado case involving a zip line collision illustrates well the intricacies of events such as we have described.


Lisa Cowles v. Bonsai Design LLC, et al, was filed on July 5, 2019, in the U.S. District Court of Colorado. The facts below are as recited in the court’s published Order On Pending Motions, dated June 5, 2020. They are largely drawn from Plaintiff’s Second Amended Complaint. We focus on those assertions, knowing that some were disputed by the defendants, as they can help us understand, and meet, our duties to our zippers.

The background. One of the defendants, Bonsai, designed and built a canopy tour for The Vail Corporation. The project included a number of zip lines and a custom braking system with primary and secondary (emergency) braking components. There were no components which allowed zippers to control their speed or to stop. 

According to the plaintiff, after completion of construction and licensing in the fall of 2015, Bosai continued to provide maintenance and inspection services related to the braking system. In addition, Bonsai developed training protocols for the use of the lines, including 1) for retrieving and redeploying the braking system to its “proper settings”; 2) requiring staff to radio each other to advise when it was safe to send the next zipper; and 3) requiring the staff to instruct riders to look for colored flags at the receiving platform indicating the readiness and appropriate resetting of the braking system (to avoid the incoming rider’s crashing into the equipment).

Bonsai performed an annual inspection of the course on or about June 5, 2017, and certified that the course and components and equipment were in an “operable state.” In the following several weeks, however, two riders were injured on the course, including as a result of a braking system failure.

The incident that led to Cowles’ suit occurred on July 7, 2017. Plaintiff Lisa Cowles and her husband were part of a group of “six to eight” participants. Plaintiff, and presumably other members of the group, signed an agreement which purported to be a waiver of claims against the “Activity Operator….(and) equipment manufacturer.” (The existence of the release was not mentioned by plaintiff in her complaint, but was considered by the court—over the objections of plaintiff’s counsel.) The group then received “a short instruction” by staff and assurances about the integrity of the equipment. Nothing was said about the recent system failures.

The group successfully travelled down several lines, observing staff and following the aforementioned protocols regarding radio contact and “all clear” signals, before weather briefly interrupted the tour. When it resumed, Plaintiff’s Complaint asserts, the Vail staff changed their supervision and management of the group. Plaintiff noted, for example, that the guides were “not regularly waiting for radio advice” from below before sending riders down.

The accident. Plaintiff began her ride. As she descended, she was unable to see the flags below indicating the readiness of the braking system. As she approached the receiving platform, according to her complaint, the waiting Vail staff member was “jumping up and down and waving his arms.” Plaintiff collided with the first component of the braking system, which did not slow her momentum, and the system then “appeared to fail …or explode.” Plaintiff collided with other components of the braking system and/or the tower and platform at a “high rate of speed.” She suffered multiple fractures and head injuries.

Ms. Cowles filed suit on July 5, 2019, against Bonsai, The Vail Corporation, and other Vail affiliates. The original and subsequent amendments pled negligence and gross negligence, and premises and products liability.

The outcome. On June 5, 2020, responding to Bonsai’s motion to dismiss the complaint, the court ruled that the plaintiff had waived her right to sue for negligence under these circumstances. The court did, however, grant permission to plaintiff to amend her gross negligence claim, a claim which, under Colorado law, would not have been eliminated by the signed waiver/release.

The case ultimately was resolved by the parties without the necessity of a trial. 


What are the lessons learned from the circumstances of the reported collision and the action of the Colorado court?

The accident occurred “in plain sight.” There can be little doubt that plaintiff collided with equipment on the line and, likely, with some aspect of the receiving platform. It would be difficult, based on the facts as presented, to find any fault on her part. And she clearly was badly injured.

Details matter. If plaintiff’s allegations are true, a defect in the braking system can be traced reasonably to the designer, manufacturer, and installer, Bonsai. There is evidence of a defect in, or at least recent mis-performance of, the system. 

But there is much that is not known:

We do not know if or how the operator of the tour reacted to these earlier incidents.

We do not know if the defect was earlier discovered by Bonsai in its role as inspector of the course, or if its findings were reported to Vail. A cynic, or plaintiff’s attorney, might suggest that except for the commissioning inspection by a builder, inspections might be done more credibly by an independent third party. 

It is possible that the braking system was in fact in good order but had not been re-set at the receiving platform. A major cause of plaintiff’s collision, then, may have not been the equipment but, rather, the lack of communication between the sending and receiving towers. It appears that the signaling and readiness protocols had been taught to the staff. Which leaves open the argument that staff did not follow those protocols and training.

Plaintiff’s complaint asserts that Vail’s zip line staff may have changed or relaxed their operating routine after the weather break, but that issue is not developed in the published court order. It is probable that industry standards were violated, if plaintiff’s rendition of the facts is correct.

Nothing suggests a defect in the design or construction of the towers or cable, or any terrain issue.

There is no evidence that the zippers were aware of the prior issues with the system or knowingly assumed those risks. The collision, as it occurred, would not likely be considered an inherent risk of the activity.

Significantly, the court found that plaintiff did sign an agreement, releasing Bonsai (and Vail) from liability for their negligence. The agreement, however, did not release either Bonsai or Vail from gross negligence. The case could have proceeded on that issue, and that may have provided an incentive to reach an out-of-court settlement.


Carefully consider the circumstances of the Cowles case in light of duties owed, duties breached, and defenses to liability. Understand, too, the importance of documenting training, inspections, and maintenance procedures and outcomes to provide clarity and demonstrate compliance with duty of care responsibilities. 

When you contract for services, consider your exposure to claims for which others might be responsible, and protect yourself accordingly.

In considering the fundamental legal concepts described here, and their application to the reported facts of the Cowles case, owners and service providers are urged to consult with legal counsel familiar with their operations and laws applicable to them. 


About Author

Leave A Reply