I don't think it's that the rich don't want to help, but they are accustomed to fending off people trying to take their money. Deal with it often enough and everyone looks like a swindler--it's a bit like the experience of moving to the big city, and learning that it's better to brush off 100% of the people on the street who have a sob story, just need bus or subway fare, or claim to have gotten their car towed.

Also, in rich neighborhoods, the police have the time and inclination to speak with unlicensed door-to-door peddlers. It is unquestionably in the wealthy homeowners' interests to discourage both solicitors and burglars from wandering the neighborhood, knocking on doors, seeing who's home and who's not...