Just read most of the thread and personally feel for the OP, surely it would be easier to police a smaller NFZ and maybe take out any UMA/drones that enter it, which lets face it wouldn't take anything more than a rubber bullet, I'm sure they have military drones poised ready to attack.
I totally agree with a forced NFZ around airports or government buildings but a 40 mile NFZ around DC? which will only keep dji drones grounded, that definitely seems a little over the top and a knee jerk reaction to paranoia and lets be honest model aircraft have been around for many years and can be flown without forcible restrictions, I am pretty confidant they would be the craft of choice for the prospective terrorist.
In the UK you cannot own a gun without a licence, which from what I understand the process is quite stringent, my work colleague, who has a shot gun licence, recently had it revoked because he got charged for being drunken and disorderly on a night out, not whilst handling the shotgun I might add. There are still over 8000 gun related crimes committed in the UK every year. My point is a 40 Mile NFZ is only going to stop normal everyday Joe public from enjoying flying their drones, nothing more....IMO.
PS.Obviously my comments are related to drones but I'm assuming that the NFZ around DC is for any aircraft, manned or unmanned, but surely the same restrictions shouldn't apply to drones or at least to anything the size of a Phantom or smaller?