Welcome aboard, Deborah!
Pirate Night on Disney Cruise Line is such a fun evening of swashbuckling games, a pirate-themed menu at dinner, characters in their pirate gear and of course, Mickey's Pirates IN the Caribbean Deck Party, complete with Buccaneer Blast fireworks at sea!
My family really enjoys dressing up as pirates that night, as do many other guests. I completely understand your question about packing a plastic pirate sword, as I always felt hesitant to do so too. Rest assured that I've done this many times after my initial hesitation as my five-year old son says a pirate isn't a pirate without a sword or hook! Go ahead and pack it in your checked luggage, just to be safe at the airport. Then, yes, feel free to let him carry it on Pirate Night! The Fantasy sells pirate play swords, hooks and other scallywag pirate gear in the gift shops, so if you forget any pirate must-have's, you can easily pick up another there.
Also, check out the
Pirate's League in the Bibbidi Bobbidi Boutique. My son had the time of his life being magically transformed into Black Beard there on Pirate Night! It's a once-in-a-lifetime experience that is worth every penny when you see how much the kids enjoy it!
Happy planning, Deborah and please stop back if you have other questions before you set sail!