Fair disclosure, I fly a Phantom drone...
Anyone flying responsibly will be nowhere near 4,000ft or 9,000ft, the CAA recommend 400Ft as a limit. The DJI software even lets you set up limits, and again most responsible fliers will have them set already, I know I do...
I'm not trying to excuse the behavior of these idiots, I happily see them fined or imprisoned if they put people at risk, however as the people flying them have no consideration for the law as it stands, why will bringing in more laws, that are pretty much going to be impossible to enforce, help? The power to prosecute already exists under the Air Navigation Orders that are already law.
Biting the hand that feeds IT
