Another point to consider is that the UAVs in the Dulles and Love Field were probably flying within the confines of Class B airspace. Flying in Class B airspace requires a clearance from air traffic control, and continuous 2-way radio contact with ATC. If the FAA was able to catch the pilot of either of these quads, I think they could convince a judge or jury that the pilot was endangering full-scale aircraft, as they were not following procedures that are designed to ensure the safety of aircraft and passengers.
If and when the authorities are able to catch one of these idiots, I imagine they will prosecute him/her aggressively, in order to make a point.