Same thing happened to me two weeks ago flying TED from IAD-TPA. It was definitely not an oversight as the gate agent specificly announced via PA system that boarding order would be 1,3,4 and then 2. And yes, they turned away 2's who tried to get on early. Like prior poster, I was a bit annoyed to have to wait and then find my overhead storage space already full, especially since I had just shelled out the $299 for a year's worth of E+ access.