RDG (Reading, PA), 76 daily seats, did have the US Express employees doing the security screen for quite some time after the TSA formation. Once checkin closed the chain gate went down at the counter, employee scurried 20 feet down and opened the chain gate at the security checkpoint. It no longer receives scheduled service but I think TSA is shuttled in for Southwest charters.
More recently I flew out of MCW (Mason City, IA) Half a dozen TSA agents for the 4 flights a day, but the chainlink gate was still used. Screening opened 30 minutes before boarding and after departure the gate went back down and the screeners went back to coffees, no pretense of standing around for these guys.