I can't remember at DHS, but at Epcot, MK, and AK there are "lines" for folks without bags (so I'm guessing there is one for DHS as well). Look for the signs at the entrance to the bag check area. Basically, it's another check point, but only for folks without bags. There are security CMs standing there, but they're just checking to make sure you're really bagless. As long as you don't have a bag, they'll waive you through.
At the International Gateway, there is no line for folks without bags (at least that I recall seeing in October). You still have to wait in line to get past the check point. (I suppose you could try to skip waiting in line, but you'd end up having to squeeze/push past the folks that are already in line.) Once you get to the front of the line, it'll just go faster because you don't have to wait for the security CM to look through your bags.