How to prank people using Google Glass

There is so much fun that could be had with Google Glass. We imagine some scenarios

One of Google Glass’ features that both delights and aggravates users is voice control, but it could also be used by inventive pranksters for some really cool or annoying effects. And I don’t mean how a wearer of Google Glass could prank someone else, but how someone could target an individual Google Glass user, or every Glass wearer in a particular space.