I used to donate to every panhandler; figuring that no one would put themselves through the humiliation of begging without a sound reason.
Now, I think donating is like spilling sugar on a picnic blanket. Just as the sugar attracts ants, the donations just attract more panhandlers. I donate to registered charities instead.
I also quit giving to panhandlers.
I found the panhandlers in Vancouver, BC (Gastown) are quite aggressive.
I heard that some of them make $200-400 a day.
It seems that once it is an accepted practice, it becomes entrenched.