system
A chat on subreddit /r/wallstreetbets
human
So not only would a lot of hosts experience shitty customers who do all sort of shitty things but they would have to pay to warn others? 

That's a really stupid idea though well intentioned.
gpt
I'm spitballing because I use properly licensed hotels. But I thank you for the criticism. My thought is that 3 stars would be free, and enough of those will drop a renter rating. But some form of paid "fuck you" would be powerful. And the possibility of no repeat business from that customer is not enough.

Sellers shouldn't get to take all the money AND say fuck you to their customer. If you say it, put some skin in the game.