Originally Posted by
DCA TSO
Different airports have different levels of security. You might be able to keep your flip-flops on at Hilton Head Airport or your Crocs on at Rutland Airport in Vermont, but at DCA, which is a "cat-x" (highest level of security) airport, you and every other passenger are required to remove your footware.
Why should checkpoint screening be any different at any airport unless you do gate screening and different levels of screening depending on which airport you are flying into. Otherwise, if screening is too tight at DCA, then one could just fly out of an airport that has a lower level into DCA and then make a connection airside, thus avoiding the supposed higher level of screening at DCA.