I think it would be unlikely that the user would step away from his machine before unplugging the device. If it was discovered on the ground, I would think the likely sequence of events is: 1.) plug in, 2.) open finder, notice nothing of interest. 3.) unplug, 4.) discard
So then, one tactic would be to fill it with nested folder after folder of something that might be interesting. Like "Studio Rough.mp3" If you make it large enough, a lot of people will procrastinate going through it all.
