Marfitalu: Just search back - that has been debated many times before here.
It is of course against the "official" backgammon rules that you should move with both dice if possible.
But it is a known problem on BrainKing that it is allowed - so some have said since it is allowed, it is OK to do on here. Other say that even if it is allowed, to be true to backgammon - you sould not do this.
Which is correct? Well like I said, read back and check out the debate... both sides are correct in a way. :-)
My personal feeling: Cheating? No, I would not call it cheating - unsportting - possible. But then again, you have to assume that the person was paying attention and knew there was another move to make. I've done the 1 move thing without even noticing until after it was pointed out to me. When I'm playing quickly, I spend about 10 seconds looking at each board as I move... so it is an easy thing to not notice.