My friend is currently doing this. I view it as subletting without the additional paperwork. Ultimately my friend will be reasonable for any damage or disturban

My friend is currently doing this. I view it as subletting without the additional paperwork. Ultimately my friend will be reasonable for any damage or disturbances. The thing we're trying to figure out is if this approach can scale. Currently his second apartment is leased by his fiancee, who is out of the country for school. Beyond 2 or 3 apartments I'd imagine this approach would get a bit dicey.