Ron, one of the justifications mentioned earlier for extra invasive searches was the potential to use the plane to destroy a target (9/11 style). The cockpit door solves that.

The passenger vigilance means that it is more difficult for any group to do stuff on the plane itself. A single person may be able to assemble components of a bomb, but is more likely to be noticed and stopped today. If a group wanted to do more than that on a plane, they now have to factor that it will take a larger group of people to make sure that the passengers don't stop them. The larger the group, the more likely that they will be noticed ahead of time.

In other words, it's now much more difficult to get effective results from any on-board activities. What we now seem to be targeting with the searches is the single crazy person who is trying to cobble together a science experiment type bomb. We are using the latest failed effort to inform our search efforts. At what point will we say enough is enough? We should be asking the TSA and the Canadian equivalent to show some research that says their efforts are actually resulting in increased security.

Those that really want to cripple air travel can just as easily do it at the airport itself. Do we need pre-screening areas to deal with that risk? How far to we want to go with this?

My point is that a lot of the increased airport screening isn't necessary and hasn't been shown to be effective anyway. It's a powerplay effort to show that the "authorities" are in charge. As a citizen of a free country, that bothers me a lot.