The kids get a wrist band. The adult plan gets a sticker on the sail and sign card. And yes as stated above it is good in the dinning room just let them know when you order. The only time you can not us it is for room service.
make sure you purchse the kids soda band from the youth counselors, during the orientation for the kids program the day you sign onto the ship.Its about 16.95 i believe. You can chose from either a cup or a band, get the band, otherwise the cups are easily lost, and NCL doesnt' replace lost cups. The adult soda program is much more expensive.