99 out of 100 are scamming you. Do what you want because as others have said you should help people in need but you are also enabling a lot of drugs and alcohol abuse. No right answer here. If you travel enough you see the gas station scammers daily. When I worked downtown a lot I would see the same ones day in and day out. Same stories, same gas cans, broken fan belts, whatever the story of the day is. I lost patience for them years ago, I give to the church and some other charities but never to people on the street.