Soldato
I always keep my room cards from all hotels when I leave, or just give one back on check out. The amount of times I have been to Cosmo, Aria, Wynn, Encore pools just flashing an old hotel key card is countlessPretty sure you can't. You need your keycard to get into the pool area and there's a member of staff at the entrance. They want to sting you with those poolside beer prices.