I have been a host for years. I have been a guest. I have been injured as a guest. The problem is a piece of paper is fine so long as the host is going to ensure the safety of the guests. I can't speak for you, but I did and thankfully I never had an incident with an injured guest.
Several weeks back, my host did not, and I became an injured guest. Ethics are involved here. Lawyer can offer a blurb, but what's going on in your home... and your heart? Are you gonna strut around with a piece of paper while someone's world is turned upside down?
If the answer is "yes" then you are like the company that made you have to go to your lawyer to make sure people are taken care of.