I always do because I was taught, there but for the grace of God go I. If someone needs money that bad they have to beg for it, I will give them something. Many people dont take this view and i suppose it is to do with their upbringing and their political and social views.
Be interested to know what you all think though. Bearing in mind, many people, particularly the young "suits" are only a paycheque away from the street, despite earning huge salaries. Maybe that is why I often see young suits haranguing street people - cause they know that could be their lot too.