I appreciate your seeing my point. I do agree with you that we may never catch a bomb going through the checkpoint. However just that particular situation happened at the Blaine, Wa airport this past year when a fisherman decided to carry through modified sticks of dynamite that he called "seal killers". No, not a terrorist, but the screeners did a job that they, themselves would have probably agreed with you might never happen. Regretably it takes only one successful attempt to cost hundreds their lives. If I, or any of the other screeners here or at the checkpoints can do something to prevent it from happening, I think that we have been worth it.
I also agree with you that these are new times. If a terrorist were to attempt to take over an aircraft now with a knife or box cutter, even a gun possibly, then I for one commend you for the attitude that you will put yourself into a position to do something about it. And yes, there are armed security personnel on planes moreso now than before. The problem is that, the way fate is the hyjacker will be lucky enough to pick the airplane where these precautions don't exist. You have said yourself that it can still be done. Will we at TSA on the lanes be able to stop it? I don't know, but I am willing to try.
Thanks for the post.