I work in SICU. Our baths are done on night shift (I work days) at very odd hours and are preferably done when family has stepped out. That being said, our patients are cleaned up more than just during the bath at night for various reasons... incontinence, leaking rectal tube, leaking tubes & drains, oozing wounds, etc. I can't imagine that any nurse would just yank the sheets out from under him and not clean him up as well.
I should also mention we actually don't give the traditional bed baths,we use wipes specifically designed for ICU type patients which create a barrier that help prevent/ decrease infection. The effectiveness of the wipes is decreased when lotion, soap, etc is applied. Ovbiously we clean our patients the traditional way when they are soiled, but I have had our patients state that they were not given a bath because they had not been washed with the expected bed bath, or allowed to travel to the full shower with their many drips, drains, etc.