Leasing short sale purchase to current owner

[Hung Nguyen]

I'm pretty new to RE investing and found a condo where i met the current owners in a short sale situation. I asked if they wanted to lease the unit if i were to purchase it and they agreed. Is there any rules against not having the existing owners stay and lease the unit after you purchase from them? I think its a great opportunity since I saw how well they took care of their place and got the feeling they didn't want to leave but am also scared to run into any pitfalls that are unforeseen with this investment. Any advice or suggestions are happily welcomed. Thanks