Very fragile. It always baffles me how close to the ground airplanes fly during take-off and landing and how there aren't lunatics messing with them more often. In the US there are places where it is legal for a regular Joe to stand underneath an airplane on approach, 200ft off the ground with the type of gun/rifle that could cause serious damage and bring it down.
I'm not sure what you're trying to get at here. Doing such a thing is already illegal, so making it illegal to also be under the flight path won't stop that person; by definition, they already don't care about the law.
Presumably if it were illegal there would be some security in place. Maybe a fine, but maybe even a security camera, or a larger fenced area, or whatever. Something beyond nothing at all. My home depot has more security around the garden center than the fringes of the airfield at LAX. Right now you can picnic under planes taking off right outside LAX. If you wanted to invoke some asymmetrical warfare, just open your picnic basket and fly your quad copter drone straight up into the flight path.
I see where the commenter is coming from. We spend millions of dollars on technology that can see your manhood perfectly through your clothes, yet 300 yards away from every TSA checkpoint at any american airport is some rusty po dunk fence where you are pretty much in range of striking the engine of a jet plane with a well flung rock. It's an asymmetric warfare specialist's wet dream, and the whole purpose of creating the TSA was in response to asymmetric warfare. It's baffling why we even bother, unless you remember that people are making a good deal of money off of this graft selling manhood scanners to the taxpayer.
