Here's a good anti-creep tactic for beginner sessions.  Sorry to generalize, the usual suspect is an older unattached man who comes early and makes himself all too available to the prettiest new dancer.  Before you know it, he's running his own 1-on-1 workshop.  I let him go for a while, but when it appears the behavior is predatory I get them in a circle and teach them how to allemande.  Then I say "With this partner allemande R 1 1/2, then move on to the next and allemande L 1 1/2, then to the next and allemande R 1 1/2, etc." until creep and prey are far apart, and then " take this one as your new partner for some more."  This also breaks up those newbie couples who came joined at the hip.  Of course, at the same time they're learning a progression and how to adjust to each neighbor, so it's seems like real teaching.
 
This circle technique also works well to safely teach swings.  Now those "gentlemen" who forced me to learn this no longer come early when I'm calling -
 
Bob