I have learned (and luckily my lessons have not been hard ones) just to say no to anybody's sob stories. I don't give money for any reason.
I don't mind helping the poor, my home has been converted into a hospital a couple of times. I will treat the ill for free. (my bedrooms are kept locked and I don't have anything valuable that they can carry away in their purse or pockets). I don't use meds, and that saves me a lot of legal complications. If they need meds I send them to a medical doctor.
Both my wife and I can say no without guilt; we do so firmly and without rudeness. People catch on pretty quick that we are not their money bags.
We actually practiced saying no and I needed more training than my wife ;)
I owe these people nothing.