Great video and social experiment. In many parts of the US, a lot of kids who beg are actually victims of slavery, they have some kind of pimp who takes the money, and they are often abused. I've seen this time and again working in human services in our city.
Rather than giving money, I will take someone to the store to buy a meal or groceries, and then use that time to talk to them and really hear their story. I also try to always carry resources for shelters, food banks, homeless youth programs, etc so that I can provide those when they're interested.