I watched a report this morning on CNN about a gang of of thieves in Brussels, who will cut through a fence (or simply drive through it), force a taxiing aircraft to stop, board it, and steal any valuables on board. This has happened apparently several times in Brussels, and has also happened in Paris CDG and other places.
The response is probably going to be stronger and more-difficult-to-see-through fences., and spotters on the fences, especially those with ladders, are going to attract much more attention than they used to.
In addition, this weekend in Geneva, I caught a visiting spotter cutting a hole in the fence with heavy wire cutters! The guy was German, but I didn't get a name, and I chewed him out royally, and threatened to call the police on him, at which he disappeared (I'll probably find a hole in some other fence over the next few weeks).
This is the kind of crap that is going on more and more, and will inevitably cause airport security to restrict access and visibility (and I can't say I blame them for it).
So if you see someone with a wire cutter, especially if he's from out of town (he doesn't care if they get strict after he's left), don't hesitate to call the cops. If you don't have a cell phone handy, beat him senseless. I'm sorry I let that guy off so lightly - he'll just do it again elsewhere. A bigger impression is needed.
The only thing you should feel when shooting a terrorist: Recoil.