To get back to the earlier discussion about having to reclear security upon arrival to the US...Actually, it seems that there would be an easy way to change the setup so that arriving passengers would not have to clear security upon arrival to the U.S. because of having contact with their checked luggage (of course, perhaps the security staff of other countries is not trusted, but this is a different issue).

At some pre-clearance airports, one does not have access to one's checked bag and instead, looks at a picture of one's bag on a computer screen upon arrival to verify that the picture is of the traveler's bag. Except for cases of secondary inspection, the passenger never has contact with his or her bag at Customs. It seems that this type of situation could easily be setup for Customs in non-preclearance airports. Perhaps there could be two lanes, one for passengers arriving to their final destination who would pick up their bag and one lane for passengers who are connecting to another flight who would instead look at a picture of their bag. A barrier could be put in place to prevent passengers from switching lanes.

In the case of a secondary inspection, the agent could tell the passenger that he or she is not allowed to touch the contents of his or her bag (with only the customs agent being allowed to do so) which would thus prevent the passenger from potentially being in contact with items not allowed in the secured area. Or it could be setup where only connecting passengers who are sent to secondary inspection have to reclear security.