But maybe that's ok. Maybe preserving our privacy and avoiding making us all feel like criminals while we're traveling is worth a successful attack every now and then.
Yes, I know: easy for me to say, not having been on that plane, and never having lost anyone to terrorism. But I'd argue that the people who have been victims of terrorism (directly or indirectly) are way too close to the situation to be able to make a decision like that for the rest of us.
What is so magical about planes that make them such huge terrorist targets? How many passengers are on your average commercial flight? 200? 300? Hell, you could kill that many people just by setting off a bomb in the pre-security section of a decent-sized airport on a moderately-busy day -- and it would be comparatively trivial to accomplish.
This attacker screwed up and got tackled before the detonator was able to set off the PETN - the next one will likely be smart enough to set off a bomb in the bathroom.
I actually am very interested in hearing what alternative approaches there are out there.