Distraction is also a major factor.

The unnecessary barking, the loud and pointless noise pollution of senseless airport loops, the personal conversations and the cellphone use all contribute to TSOs missing what's relevant.

Local priories are also a factor. Emphasize fake IDs and fancy perfume bottles or lifelike artifacts or start pressuring TSOs to confiscate more to prove they are alert and the mission itself gets distorted.

I have had a TSO hold up a hand for me to wait while she finished typing on her cellphone and then said something to another TSO on the other side of the belt. Way to go folks, got your mind on everything except your primary task.