Risk a terrorist getting through, or kill an innocent person? If you shoot down the plane and it IS a terrorist, that's the only scenario that even remotely gives you a win. Oh, wait. What sort of things would be carried by a terrorist on a light plane? Germs? Gas? A suitcase nuke? Okay, where did that plane come down when you shot it out of the sky?
A tough scenario, and possibly, like suicide bombers, one of those things that is almost impossible to prevent once launched. This is why America and Israel have a policy of trying to wreck the infrastructure that spawns these things. Biowarfare or nukes implies a large organization somewhere in the picture, and even properly-designed belt bombs take a fairly decent facility to get the materials and produce them.
Current Events » in reply to I'll bet that's one post you'd like to take back.
The old "can't win" dilemma