Charity spokespeople who promote their charity on high-traffic sidewalks by cornering tourists and other innocent passers-by.
Charity Hooker: Hi ma'am, do you care about free trade?
Innocent walker: Um, yes. Well no - uh, I have to go...(walks away hurriedly)
A hooker who does her work for free.
"Mary is a charity hooker, always thinking of her clients. Isn't that the hooker you want on your side?"