Rather than spend $$$$$ to have a TSA employee sit on a stool at every concourse exit (at every USA airport) why don't the airport install one-way revolving exit doors. This would eliminate the possibility of someone running into the secure concourses without going through the checkpoint screening.

Note: of course the badged airport employees and vendors with gate clearances will continue to enter/exit the secure areas of the airport(s) without ongoing screening.

RC