It's not like deer have witnessed humans taking apee and then went over and smelled the spot and had the thought, "Hey, I now know what human piss smells like." Instead, they will see us walking,recgnize our human form and know what our bodys smell like, such as your body BO. They aren't smart enough to put two and two together to no what our piss smells like.
I pee out of my stands all the time with no ill effects from the deer.