I respectfully disagree.

Every time I've been randomly selected, I have been asked to identify my bags and they are brought by the agent to the secondary screening area.

If I fail the swab test (which I often do because I'm not going to stop wearing lotions that contain glycerine every time I fly), then my bags are manually inspected. And during that manual inspection, everything is swabbed and checked.

So I still think there's a problem here. If my bags were considered cleared, then TSA wouldn't be manually inspecting them when I fail a swab test. But given current procedures, one can easily avoid having their bags manually inspected upon random screening with the simple cooperation of a travel buddy.