I don't have any direct experience but follow a few cruising forums. You should definitely be as low key as possible. The Disney crowd will narc you out if given a chance and if caught, or even suspected, they will put you off the ship in the next port, which can be an expensive lesson. Bring your passport and not just a birth certificate.
Bags are x-rayed and selectively searched, don't give them a reason to pick yours for a hand search. They are mostly looking for prohibited electric appliances (curling irons) and bottles of liquor.