Originally Posted by
Boggie Dog
Just my 2 cents, if you know you will likely alarm a WTMD then ask if you can do Pre in a lane with AIT. Otherwise you're not gaining any benefit from Pre and should go through normal screening.
The Pre line, especially at DCA, is measurably faster and if you are Pre and require a secondary, as OP did, an Officer will escort you to the head of the line. While an annoyance, it will still be a good deal faster than the standard line.
As to the carry-on stuff, do put it all in your carry-on and simply ask the Officer to bring the bag with you when he escorts you for the secondary.