Every now and then I'll be shopping and the security device by the door will beep as I'm walking out, even though I haven't stolen anything. I always just assume there's been a mistake, e.g. the cashier forgot to deactivate my security tag, and walk straight on out; I'm not going to waste my time being searched when I know I haven't done anything wrong.

This doesn't happen very often but as far as I can remember I've never been challenged when I do it.

But what I find really interesting is: based on what I've written above, isn't it trivially easy to guess my skin color?