But that's the point, it's not clever. It's blindingly obvious, virtually impossible to stop, and it hasn't happened. So terrorists are either incredibly stupid or extremely rare. Either case suggests that we are spending way too much in both money and freedom defending against the alleged threat.

I guess we'll have to start screening people before they get in the line, then.

Yes. Very clever. Where else could a terrorist find a crowd?

I just hope the TSA figures it out before someone with a bomb does.

What can they do? There's gonna be a line somewhere. And most airports don't have room to make it straight instead of coiled.

Ultimately what we can't do is to entirely rejig our society to prevent people from being densely packed in any place at any time just in case somebody decides to set off a bomb. The best thing we can do is to keep suicide bombers fixated on hard targets like aeroplanes so they forget about soft targets like... well, whatever.

How about we just give up on the whole farce altogether? The TSA isn't making airplanes any safer from bombers, period.

Think about it: If they'd had a single success, just one instance where they stopped someone from doing something bad, they'd be screaming it from the rooftops every chance they got. Since they're not, and we haven't heard of anything more malicious than grandmothers with nailclippers, I think its safe to say that the TSA hasn't done a damn thing.

Actually there are a lot of technological and policy solutions to "big line at security screening, potential bombing target itself"; in environments where the attackers were still idiots but actually existed (unlike US airports), these solutions were implemented.