Good idea. What do you think I can do when I'm on a train and there is nothing I can do but to give money? That where I get to hear most of the touchy stories.
Everyone has a story. It might be you another time so be respectful but if required be polite but firm and refuse. If its a train they will move on to the next person/carriage. If they are telling you a story, then take the lead and ask them questions. Such as they want to go home, well tell me about home. Your parents, your brothers or sisters. The cute girl in the coffee shop who you went to school with. Tell me about them. Look for consistency in the story but you have to use your gut.
In my opinion, you are better off buying them the meal and food or the ticket yourself at the next stop. Never give cash.
I'm not sure I'll have the courage to speak. For example, one lady claims that her daughter got injured in a terrorist attack and for years now she is undergoing expensive medical treatments. I see this lady pretty often on the train. No way I'm going to ask her about her life.
In my opinion, you are better off buying them the meal and food or the ticket yourself at the next stop. Never give cash.