Cash For Keys?

I'm currently a renter and my property has been foreclosed on. The bank is offering me a cash for keys to get out of the hosue. I'm thinking about taking the offer but the problem I'm faced with is the house was in bad condition when I rented it. (carpet needs replaced, some holes in wall, and some walls need painted). I did a through walkthrough and doented everything. Will the bank notice this stuff and hold me accountable for this stuff and take it off of the money they are offering me. Secondly I'm also wondering if this is a scam where I move out and go to give the bank my keys and they say ha ha or something like that. The bank is Fannie Mae. Thanks in advance for your advice