Subtle Public Submission

Thinking about the Ren Faire, it's a great place where one living the lifestyle can be a little freer, without anyone being the wiser. The dress typically seen there is such that many BDSM related clothing won't receive a second glance. Plus, I can ask "My Lord" a question, or see how "Sir" is, and no one will bat an eyelash.

Are there other places you can think of where subtle submission is publicly possible without others really being aware of it?