The FAA has no choice and has been directed to find a way to integrate UAVs into the national airspace. To stay with your train analogy, not only has it left the station, its almost up to cruising speed. Its coming...no question about it.
From there I expect to see some entrepreneurial opportunities to create products that dissuade UAV use below 400 ft over private property, including tracking anti camera lasers and illegal control jammers. The later are trivial with Software Defined Radios.
Some idiot was recently arrested for shooting down a drone over his neighbors property, so I don’t think that is the answer. http://photographyisnotacrime.com/2014/10/07/man-arrested-charged-criminal-mischief-shooting-drone-shotgun/
I just cannot see the FAA letting this crap go commercial without constraints just as they use for aircraft commericial use. Otherwise we WILL have accidents with real aircraft and possible deaths. Nope, is not as simple as you represent and the penalties will be severe.
As to the guy shooting one down, he only made the mistake of doing it down over somebody else’s property. The constitutional privacy provisions will come into play and will it end up in front of the Supreme Court???
Spying into apartment windows on the 20th floor in NY? Already has happened. Flying around airports? Already has happened. Flying high over NY airspace, high enough for airliners to identify? Already has happened. Taking pictures of people in their back yard? Already has happened.
Anybody that is “pro’ of this activity is a real pervert and fan of scandal sheets in the check out aisle in the grocery store.