In another discussion about this, a worker said the front desk knows the possibility of how many would be using the pool on any given day, and she had suggested we ask there.So, we've asked at the front desk at the Disney hotels and been told yes (and we have done the same at non Disney hotels). They have wrist bands they can give out, if they judge the pool won't be too crowded.
I also have asked/talked with lifeguards because of what I read on this board (and was told by one, that that is why it's better to go directly to Disney, since unofficial boards often have unofficial info), who have acted like I had two heads when I asked them. So now I ask at the front desk. Their signs, their rules, and they (or the hotel manager) have the ability to either go by their rules, or bend them, depending on crowd levels.