Actually, I do this too, and it does work excpetionally well. To the poster who asked why do this? If done correctly, it actually does NOT reduce actually sharpness, only percieved. Those black lines around the pixels trick you into believing there is greater sharpness than actually exists. If you defocus just to the point where the pixes move slightly to cover those lines, without overlapping, you lose NOTHING in terms of sharpness, but remove the screen door effect. In fact, this is EXACTLY what the Cygnus IMX lens does, just better than what can be done with regular focus.
Sharp xv-s55u (Don't laugh) :)