Personally, I think the drone should be registered to a purchaser database and that in order to purchase one legally, you should be able to show completion of some type of training or curriculum. Part of the issue, to my mind, is that for folks who would do mischevious things, the drone becomes an anonymous extension of yourself. "Look, I can fly over the sporting event and nobody will know it's me", or, "Look, I can take pictures of these sunbathing girls" (which already has happened, apparently...). If people are made aware that the device could be traced back to them, I personally feel that it would make folks think twice about doing dumb things with them.
Erik