I remember a talk from last September I saw where the speaker showed off a few "Mobile Phone Charging Stations" that would pwn a device when plugged in. I'm sure an exploit like this could be leveraged into one of those systems for some more interesting results as well.
And while I don't see this is a huge threat for most people (most people I know are usually the only person logging into the system), but I was thinking a place like a library or computer lab in a school might be a viable place for this kind of exploit. If I would have gotten into security during high school, I would probably have gotten in a lot more trouble.