There's still some mystery as to how Google Glass works or can work, despite the fact that we know its hardware specs. Aside from voice-control and a touchpad, it appears Glass may support "winking" as a form of input.
According to Reddit user "fodawim", Glass's companion app contains code for "winking," specifically, winking to trigger the camera shutter. It's there in plain sight: EYE_GESTURES_WINK_TAKE_PHOTO.
A year ago, Google X bossman Sebastian Thrun took a picture of Charlie Rose using the shutter button on the side of Glass and nodded to share it to his Google+ account. It's unclear if the final production units of Glass that will now come out next year will support these "behaviors" (for lack of a better word to describe them).
As "fodawim" suggests, winking to take a photo is pretty darn creepy. But before you jump to any conclusions, understand that the code merely suggests it's possible to do that. The feature isn't activated by default, as it'd be kind of annoying for Glass to mistake normal blinking behaviors as "winks." The code does make you wonder something: can winks be programmed to activate other tasks?
Either way, all the perverts who plan to buy Glass probably won't know how to calibrate it, anyway.