I have a question concerning the packing list....specifically the quoted text below...
• Bring an old, outdated member card from a store that has a magnetic strip on the back. Instead of using your credit card to lock and unlock the cabin safe, you can use this instead. This way, you won't have to carry around any credit cards around with you all the time. After all, ships don't use credit cards: They bill all onboard purchases to your sail and sign card's account.
On Royal Caribbean the safe in the cabins you punched in a numeric code you selected. Are Celebrity's safes different? I am not understanding what you need a credit card for the safe.
Thanks for further clarification