N.I.
wow, you are my hero now! ha! I been wanting to do it but I'm so afraid. My friend told me she purchased that thing that you tie around the kid's body I call it a dog's collar...i know it sounds bad...but she said it was the best to walk around with him w/out being too much afraid he would go running around.
I was thinking make sure you double up in all medicines including nausea medicine, just to make sure ask your pedriatician which one is better...because everything is expensive. And yes there are ways to contraband food in your hand luggage, take snacks you know he/she will eat just in case he/she gets picky. Which you know some kids are, mine is one of them.
And maybe some of his/hers favorite toys or teddy. Or even a blanky to remind him of his home. If this is your first time w/him/her on a cruise you want to be ready for anything and then the second time you already know and will be easier.... and let me know too!
good luck and I hope you have fun!