In my experience I have found just the opposite. I have never had a deer cross my trail and spook while wearing rubber boots. Sometimes they stop and sniff my track but never become alert. When I first started bowhunting i wore several different pairs of leather and canvas boots and always had problems with spooking deer that crossed my trail even when I started using cover scents the deer became alert. I even wear hip waders to a few stands because of the tall grass. I boil green pine needles and bark and put the liquid in a spray bottle to use as a cover scent. Works great.
I just ordered two pairs from Cabelas. They have a new lightweight rubber/neoprene boot uninsulated and one with 600grams of thinsulate for later in the season. Dont leave home withoutem.