I'm sure I have before, but I generally don't give money to people asking for money / panhandling / etc.
The link between panhandling / begging / etc and some sort of vice like drugs or liquor isn't an excuse, there's a pretty strong correlation there. A lot of people who are begging on the street are on the street because their addiction/disease keep them out of places that are there to help, or, they develop a healthy skepticism of those places as some relationship to the addiction/disease.
"Hey, can I get $5 for the bus? I got off at the wrong stop."
Chances this person isn't 100% a scammer is pretty low.
These are pretty common in my city, too. I politely tell them "I'm sorry but I can't help." Very rarely does someone follow up after that. I got had by one of those guys about ... 15 years ago. I don't know why I believed him, but I did, and it was my birthday so I think I was feeling "generous" or vulnerable maybe, and so I gave him $5, but he saw I had more money and he's like "Man, the train is just $8 if you gave me $3 more I could get back to where I was going..." or whatever, so I gave him $10 total. I just didn't think about it until later, he was really convincing... but just none of his story made any sense about 30 seconds later when I stopped to think about it.
I then saw him about 3 weeks later and about 10 years later still pulling the same story. I saw him giving the story to an elderly lady in the super market parking lot which was about 1,000 yards from where he gave me the story ~10 years earlier. And ... it's one thing to try to get money from me, a naive millennial, but I kinda felt bad for this lady just walking to her car, and I thought about how my grandmother always got scammed by phone scammers... so I walked up and told him to leave her alone and let her shop for groceries, and that he had talked to me 10 years ago. He turned on heel and quickly walked away.
I'd normally not do something like that, and just live and let live, but... I dunno... I saw this old lady and just thought she's probably on a fixed income and it's not right.