777fly - the problem is, how do you even start enforcing that? I can go to HobbyKing right now and get all the parts for a 2kg drone for somewhere around the $200 mark. So can anyone else. Even if the idiots knew that they needed a license (which they wouldn't, because they never have any communication with the CASA/CAA/FAA/EASA at all) they'd ignore it and fly anyway.
Keep in mind that the vast majority of model aircraft pilots are responsible. They fly under 400ft, keep the vehicle within a few hundred metres (because it's hard to see otherwise), and keep a watch out for any traffic that might be in the area.
The people flying drones around full-size aircraft are idiots, and the thing about idiots is that they don't pay a whole lot of attention to anything (like laws, common sense, airliners, crowds of people, etc). Realistically, it'd be nice to have some major penalties that actually get applied (so that people see the potential consequences) but that means finding the pilot - which is again a very difficult thing to do.