I suppose there is always the risk of "forgetting" which is probably why POHs probably specify taking carb heat off on short final. The other worry I suppose, which is no doubt miniscule compared to carb ice, is the chance you could get a blockage close to the ground. There tends to be more bugs / dust floating around in the first 100' and if you do get something in the carb.....
Still, I'd be inclined to leave it in all the way down.....