I always try to pull up on my pedals whether they're clipped or clipless. That's how I try to maintain a nice, smooth spin on the flats. I also pull up a bit on short steep climbs to get me over the top asap. Not sure if they designed all clipless pedals to pull up on though, as I remember feeling the rear clips on my PP76 pedals lifting up on me when I pull up on the pedals...which scared the heck out of me when they did so as I think it would result in me crashing if I did pull off from them.

Chombi