The stranger never finds out, there's a good chance you've been on the receiving end of people watching.
Bitches love a good sense of humor, and it's an easy way to prove you're funny and also you have chemistry if she laughs at what you say. You're too concerned about the people being made fun of, when it's about the 1-on-1 connection. The perversion comes afterwards and you're not talking about the old lady you made fun of before.