Yes I do it sometimes in cruise servers, not being entirely in the know of clutchless shifting I go up to the next gear (with a G25 and auto clutch off) then leave the accelerator until the gear comes up, to downshift I go to neutral rev the engine then engage the lower gear. I do this mainly when I get sick of the clutch and just want to drive slowly.
Oh and I hate the auto gearbox, so that's why I shift without the clutch..and the sequential option is pretty much the same as what's above, so I don't bother to change it to sequential, I just leave it in H pattern all the time.