Originally Posted by Trollkiller

I agree that a secondary screening for those that have no ID or choose not to show it is reasonable. But the courts have not ruled that way and the one time the TSA had to prove that IDs are important they abandoned the "novel argument in its post-suppression". Maybe I am reading too much into it but is sounds like the courts would not have bought that argument.

What the courts have ruled is the search must be “no more extensive
or intensive than necessary, in light of current technology, to detect the presence of weapons or explosives;” and that the search was “confined in good faith to that purpose.”

A "random" search after the bag has been through the x-ray would be more extensive and intensive than necessary. If the TSO on x-ray sees a prohibited item like a multi-tool and that causes the "alarm" (for lack of a better term), once you locate the alarm and clear it you are done. Any more searching would be more extensive and intensive than necessary.

On the example you gave of the overly crowded bag, the search would not have been more extensive or intensive than necessary due to the limitations in the x-ray machine.

But as a policy and you correct me if I am wrong, once you have an alarm or decide to hand search a bag for any reason, you must check in every nook and cranny. The extensiveness of the search due to that policy would be illegal.