[Silhouette]

And so suddenly I've just realized, 10 or 20 years from now, it's not just the police who will be flying these things around.

On the contrary. In a year or two, it might not be just the police. In 10 or 20 years, I expect they will be regulated, a licence will be required to operate one, and they will be required to transmit identifying information at all times. Apply any argument you like that relates to driving on public roads, any argument you like that relates to handling potentially sensitive personal information, or any argument you like to do with navigating crowded airspace.