Flew out on the 21st. No problem. Security screening was quick, less than a five minute wait in line, and all they do is put your carry-ons through the scanner and make you walk through the metal detector as usual. There was also a woman checking tickets, but she was a very nice, friendly one, so there was nothing but smiles, as if she knew we were all okay, but was just doing her job. Nice touch.
However, my flight was leaving at 9:10, so there weren't too many people around. Dulles is usually more quiet in the morning, anyway.
Just be sure to leave the usual amount of time to get out to the concourses on the mobile lounge (15+ minutes) and a little extra time for the security, and you'll be fine.
Hope that helps!