Q: Is having a participant sign a "waiver" meaningless or enforceable?
In some cases, courts have upheld "waivers" and in other cases they have not. There's a difference between a "waiver of liability" agreement and "assumption of risk" or "informed consent" participant agreement. The former is a release from liability for negligence while the latter asks the participant to acknowledge that he or she understands and accepts the inherent physical risk of sports participation, unrelated to accepting responsibility for third party negligence.