No, not really. I guess someone could if they were familiar with it. They'd have to climb up there to get to it first... There's a ton more that they could get away with though, so not sure that would be their first pick. Plus they'd need the monitor to make use of it in the first place.
I'd prob be more concerned that someone would get into my outside fridge and steal my beer
After all, almost everyone has a CH751 key...