I have heard from some Creative people that they are looking into changing the glasses for Spiderman (which is already discussed), but I also heard that they are looking into putting a chip inside each one of them, and when taken past a certain point, an alert of some kind would go off.
Now don't think of it as too crazy. If the glasses are like we think they will be (fragile), then we might indeed be handing them to Team Members at the exit as opposed to throwing them in a bin. All they need to do is have a themed light somewhere that turns on down the exit hallway, to tell the exit Team Members that someone still has a pair. The Team Member then can see approximately who is carrying them.
Now what about when they need cleaning? The glasses would just be walked right past the sensor and the light will go off, but that's it. No loud alarm, nothing.