AirBnB is a booking agency when it comes down to it, used to be a flyer in the local shop or newspaper, still see those but now increasingly on line.
The practicality for a start would be challenging. I am reasonably familiar with the laws in my County and I know other Towns and Counties have different rules in my State. Then each State is different and that is just the US. How many Countries does AirBnB operate in?
I suppose you would need to have a Realty Lawyer familiar with each area, the cost of doing this would be impressive.
Let's say it was $200 per listing, there are 2 million listings on AirBnB and they change.
Then as we all know and has been mentioned here, laws change, how often would you need to check, every year?
I am not even sure there could be any guarantee that even doing this would make the situation certain, I have seen a few examples posted on here where the legalities seem unclear.
It would be a bit like going down to Home Depot and buying electrical materials and expecting them to be responible for checking it is being installed in a legal way.
David