I fly out of BWI at least 2x month. Checking at at the self-serve takes no time, and the D gate is right behind you. About 6 months ago, the D gate was a mess, with lines to the intl' terminal. They did, however, pull people out of line if it was getting close to their flight times.

I have no clue about Saturday a.m. flights, but I agree w/all those who have said that it's getting better. My experience on Monday a.m. flights has been totally hassle free, but I do remove my shoes w/o being prodded.

The line at Starbucks in D in the a.m. is where you're really going to have to worry about lines!