Sort of to answer your question...

I have a very small home, but do a lot of volunteer work with homeless youth. Street kids, if you want to call it that. During very nasty winter months, I've occasionally provided homes for some at the suggestion of the shelter I work with, knowing that they've checked them out very thoroughly before ever calling me! There has always been a "plan" with everyone agreeing on the details, and has never been open-ended. (Meaning there was always a move-out, move-on date in place...)

The experience has had it's challenges, but all in all has been successful. I'm sure the housing arrangement you've suggested would have contracts, written rules, and lease agreements for all concerned. Sharing space is more common in other countries than the US, and should be encouraged as a means of conservation if nothing else!