I've occasionally traveled for work and found myself close enough to parents (and other close relatives who I know don't mind the imposition) that I've stayed at their place rather than a hotel. It saves my employer a bunch of money, my folks are happy to see me - win/win.
When I'm staying with relatives, I do expense meals/per diem. Although they're happy to host me, they are essentially subsidizing my business travel. So if I stay over, I'm going to take them out to a nice dinner (or more) as a thank-you for keeping me in cereal, lunches, and homemade whatever for dinner.
I could see a particularly bureaucratically-minded organization take offense to this arrangement. If that were the case, I'd just stay at the hotel the next time, but I haven't had a problem.