When I was in Hong Kong and Thailand I had to deal with the same kind of people who sold (fake) watches, suits or tried to get you into a guesthouse (budget hotel).
A few lines that worked pretty well:
- (to somebody trying to sell me a watch) "No I don't need a watch, but do you want to buy a suit?"
- (to somebody who was saying: "suits? suits?") "Yes, I got a suit you want to buy it?"
- (when I was just arriving by boat on small island in Thailand and somebody asked me "where are you going?) "Bangkok!" You should've seen his eyes, so funny
So yes, humor works best I guess to break down somebody's shield