Does anybody actually have any stories of people misusing rc airplanes in said manners?  Documented stories are even better.  

2 lbs isn't exactly enough to carry guns, or a worthwhile amount of drugs short ranges.  You can't do much with 2 lbs of reactive chemicals, and it seems like there are easier ways to deliver dangerous or illegal items line of sight.  Additionally, consider 2 lbs line of sight.  Once you start going beyond line of sight you need to either add a camera or an autopilot, larger batteries, transmitters, datalinks, sensors, etc... 2lbs starts shrinking very rapidly.  Also, 100mph isn't exactly fast when compared with just about any actual sized air vehicle.

To me it just seems like a culture of fear.  Don't get me wrong, I'm sure an rc airplane would hurt like the dickens if it hit you WOT, but has anybody had the FAA show up at their airfield?  Seems like this could be an interesting topic of discussion.