It's also called "a serious anxiety problem".

AirBnB takes out insurance for that very purpose, damages are insured up to 1 million dollars.

I still don't understand why you care. If you are worried about having this happened to you, what's so difficult about refraining from renting your house out? Just... don't do that. If the people renting their houses out are comfortable with the risks, why do you need to get involved and protect them from themselves? Perhaps you can imagine that they are human beings, like you, who have made informed decisions. Perhaps their risk judgements simply don't match up with yours. Why should they make their decisions according to your risk judgements instead?

I see that you care about this but I don't understand why, since it is clear that you are neither host nor guest in this scenario, and the people who are hosts and guests are not, by and large, particularly worried about the problems you are hyping up.

> Just yesterday somebody posted about their house getting trashed by AirBnB renters. So its started already. Who's insurance is responsible?

Insurance isn't responsible in the first instance. Insurance becomes responsible if either (1) the person who is responsible has an insurance contract that provides insurance for that liability, or (2) the person injured by the damage has insurance for the loss independent of liability (obviously, this insurer will then go after the person responsible for the harms to recover its costs, if possible.)