I might be a criminal

In Saigon I was stopped by a local lady when I came out the store, with a hair pin in my hand - and she was asking me sternly if  I had paid for the hairpin? I was so surprised, nobody ever thought I could be stealing, especially so obviously, I am usually perceived as prim and proper. So I just froze there smiling and blinking. After she checked with the shop owners she turned milder, and she excused herself with "well, I don't know". And I guess she doesn't. We, westerners all look the same.