Is a ”well intended” gift really well intended if there is a string attached?

Disclaimer Yeah, this is an incident I experienced.

On the way to a meeting I stopped by the coffee house to kill a few minutes. Since I was only going to be there a few moments I sat outside instead of going inside as usual. A man stopped by me and asked me some question about Facebook and somehow the conversation lingered. During the conversation another man who was there before and not a part of the conversation placed a laptop bag on the table in front of me and motioned that it was now mine. I really did not need another laptop bag but since it was smaller than the ones I had I thought it would be a good size to take to church. After the 1st guy left and I was about to leave, the man who gave me the laptop bag asked me if it was OK and pointed out some of its features, which I seen myself already, then mentioned he was homeless and asked if I could spare $2 bucks. I did not want to accept the bag because I felt it would lead to something more, but I did not want to offend him by indicating that people rarely give without an angle. I was right, there was a string attached. Had I not been talking to the 1st chap I might have taken the bag and beat it from the coffee house thwarting the other man’s intention. Do you feel a gift is disingenuous if there is a string attached or some angle the giver seeks to use? Would you have given it back and said if there are strings attached you do not care for it? Do you believe that a nice laptop bag is a good investment even if there was a $2 dollar string attached to it?