There's not much statistical evidence to support it, but even just working on logic I don't think it makes sense. You may give them a practice shot if you don't time it right. If not, you're probably just giving them more time to prepare rather than siking them out (they are professionals after all, I could kinda see it at the high school or college level). And at this point they're probably expecting it, so the lack of icing might throw them off more.