What's funny is that this morning at DCA, the screeners were so concerned about my shoes that they didn't even bother to look at my BP for SSSS after I passed through the metal detector. I got the full body secondary for not removing my shoes, but no bag search, which is what differentiates preselected "SSSS" from retaliatory or random secondary picked by the screener. If my boarding pass had been marked with SSSS, I would have been able to escape the bag search since no one except the initial non-TSA ID checker looked at my BP.