Yes, you are permitted to bring a corkscrew on a Disney Cruise. This is a common practice for guests who take advantage of Disney's alcohol policy, which allows adults (21+) to bring two unopened bottles of wine or champagne (750ml or less) or six beers (12oz or less) on board at the beginning of the voyage and at each port of call. Bringing your own corkscrew allows you to enjoy your wine in your stateroom without paying the $26 per bottle corkage fee charged if you bring your personal bottle to a dining room. However, if your corkscrew has a small foil-cutting blade, it is safer to pack it in your checked luggage to avoid issues with TSA at the airport. On the ship, if you forget one, your stateroom host or room service can often provide a corkscrew and wine glasses upon request, though they may collect the corkscrew after use to prevent it from being "accidentally" kept as a souvenir.