The Rental Agreement probably had some type of liability waiver on it.
Here is a sample from Loveland:
THE UNDERSIGNED understand that the binding system cannot guarantee the RENTER’s safety. In downhill skiing, the binding system will not release or retain at all times or under all circumstances where release or retention may prevent injury or death, nor is it possible to predict every situation in which it will or will not release or retain. THE UNDERSIGNED further agree and understand that the downhill ski binding system REDUCES, BUT DOES NOT ELIMINATE THE RISK OF ANY TYPE OF INJURY TO RENTER. THE UNDERSIGNED understand and agree that lower settings on my bindings will increase releasability but also increase the risk due to inadvertent release, that higher settings on my bindings will increase retention but also increase the risk of injury due to non-release, and that injures due to unwanted release or retention are inherent risks of skiing. THE UNDERSIGNED understands that in snowboarding, cross-country skiing, skiboarding, snowshoeing and other sports utilizing equipment with non-release bindings, the binding system will not ordinarily release during use; these bindings are not designed to release as a result of forces generated during ordinary operation. THE UNDERSIGNED acknowledge and agree to assume and accept any and all known and unknown risks of injury to RENTER while using this equipment.
and some more thrown in with the kitchen sink...
6. THE UNDERSIGNED are advised that a person using any of the facilities of a ski area is considered a skier. THE UNDERSIGNED acknowledge and understand that a skier ASSUMES THE RISKS of the inherent dangers and risks of skiing. THE UNDERSIGNED recognize that falls and collisions occur and injuries are a common and ordinary occurrence of the ACTIVITY. THE UNDERSIGNED hereby VOLUNTARILY ASSUME ALL RISKS associated with the RENTER’s participation in the ACTIVITY and use of this equipment.
7. Additionally, THE UNDERSIGNED HEREBY AGREE TO HOLD HARMLESS, RELEASE, DEFEND, AND INDEMNIFY Loveland Rental Shop , the equipment manufacturers and distributors, their successors in interest, their affiliated organizations and companies, and each of their respective insurance carriers, agents, employees, representatives, assignees, officers, directors, and shareholders (each hereinafter a "RELEASED PARTY") for ANY AND ALL LIABILITY and/or claims for injury or death to persons or damage to property arising from the RENTER’s use of this equipment, including those claims based on any RELEASED PARTY’s alleged or actual NEGLIGENCE OR BREACH OF any express or implied WARRANTY.
8. THE UNDERSIGNED take full responsibility for any injury or loss to RENTER, including death, which RENTER may suffer, arising in whole or in part out of the ACTIVITY. By signing this release, THE UNDERSIGNED AGREE NOT TO SUE any RELEASED PARTY and agree they are releasing any right to make a claim or file a lawsuit against any RELEASED PARTY. THE UNDERSIGNED further AGREE TO DEFEND AND INDEMNIFY each RELEASED PARTY for any and all claims of THE UNDERSIGNED and/or a THIRD PARTY arising in whole or in part from the RENTER’s use of this equipment and/or RENTER’s participation in the ACTIVITY. THE UNDERSIGNED agree to pay all costs and attorney’s fees incurred by any RELEASED PARTY in defending a claim or suit brought by or on behalf of THE UNDERSIGNED.