You know, one of the things I've done (and still do), is if I'm flush and have enough to eat, a roof over my head, and a couple of extra bucks to squander, I keep a couple in my pocket to give to someone who asks. I mean, on a regular basis I've been known to stop at Starbucks and buy some over priced coffee just because I can and I like it. 5 bucks is less than what I spend at Starbucks, and it can actually make a difference to someone for a day. It can give them some food, or maybe something else that they need (even if it may be booze or whatever), it's up to them. My ownership of the cash and my say about what to do with it stops whenever I put it in their hand. What they do with it is entirely up to them. I know what it's like to be hungry and not have enough to buy a meal, and it sucks.
Then there's my belief in karma. I believe that whatever I put out in the world will come back to me eventually, and it's been that way for a long time. If they were scamming me or not, it still gives me a good feeling to think I might have made someone else's day just a bit better, and it didn't cost me hardly anything to do so. If nothing else, it kinda brightens my day to think I helped.
Scam or not, I don't mind helping when asked and I have the ability to do so. And yeah, I always keep a couple of bucks around if I can to do that, even though I live on a military pension.