once
in my undergrad days, our lecturer swiped the phone from one girl who was fiddling with it under the desk (oo-er), and he looked at it, raised his eyebrows, then handed it back, wothout saying a word. she went puce, and looked like she was going to die of humiliation.

It turned out later that she'd been snapping pics up her knickers during class to send to her boyfriend.
( ascorbate, Tue 13 Jan 2009, 21:29, Reply)