From the legal eagles:
Every rental requires customer acceptance of a rental agreement and liability waiver.
That document, which is presented in full during the booking process and requires acceptance by checking the agreement box, states more fully what is summarized here.
In short, the customer assumes all risks for injury and death of all members of their group, and all risks of property loss and/or damage.
In addition, the customer agrees that the processing of the rental transaction with a credit card or PayPal account is explicit agreement to the terms.
Such agreements and waivers are part of modern life and should not come as a surprise to anyone. The terms are non-negotiable, but All About Water will be happy to answer questions about the document.