Actually none of the pools are really part of the waterpark....they are all part of Atlantis. Certain pools are for guests of certain hotel towers, so not even all guest can use all pools. Last year when were there the beach break only includes the beach and you can wander the property and you can try to go in the pools but this beach pass does not give you full access to the property, you either have to purchase the waterpark or a room to get that.
I have seen people go in and never get bothered and I have seen people been asked to leave, I guess it depends on the staffing and who is working. Have fun.