Soz, I couldn't resist.
Maybe your best approach would be to select whatever escorts you are interested in and then perhaps PM a few reviewers and ask their opinion on how discreet the location is? Obviously this works best with resident escorts rather than touring ones.
Once you're not asking for the actual location and just querying how open or discreet it is I would expect that you should get some replies.
Also it may be that you're over-thinking this and thinking it's obvious what's going on when you enter a hotel or apartment. The simple truth is that most people are too caught up in their own shit to take much notice of what other people are doing unless they're going out of their way to be noticed. Just stay relaxed and casual and most people won't bat an eye.