I notice the effects of the recession – I always offer to buy food, and in the past beggars often concocted elaborate excuses why I should give them money instead of buying a hotdog or something. But in the last few years, more and more they agree to get the food (and actually eat it).

Anyway, depending on where you live, there might be organized teams of professional beggars who are exploited by their "owner" and they have to give him his daily share "or else". By not giving money, you really hurt the beggars - but this amounts to emotional blackmailing, so perhaps you should not - for the price of hurting a few beggars now we could close the exploitation later, since if there is no profit there is no incentive to exploit the beggars.