The Nigerian Prince (or the Russian hacker) is going to rip your grandmother off for far more than any of the minority street gangs will. That's the point.

Predatory sales tactics to the elderly is a serious problem, especially to elderly people living alone. The legality of it is in a gray area because of decreasing business regulations. A lot of salespeople are instructed to deceive the elderly, to say the kinds of things they'll fall for, and for the most part they get away clean. This is a much bigger threat to the elderly than violent crime, even in high crime areas.