waiver's are worth what they are written on
There is a general misconception prevalent in the horse industry – that a liability waiver will prevent lawsuits from being filed. Nothing could be further from the truth.
Even if a waiver has been signed, if a barn owner or manager behaves in a negligent manner or was aware of an unsafe situation but allowed it to happen or did nothing to rectify it, and many other things, they can still be held liable...even with a waiver. Waivers do not eliminate the potential for being held liable. They minimize it a bit but in no way make a farm sue proof.
Even if you as the farm owner have done everything right you can still be sued. And can spend a lot of time and money defending yourself in court.
Bottom line is it's their farm, it's their rules. When you have your farm, you can make your rules.