You can register kids going to the Oceaneer Club and Lab in advance online. You will still need to check them in and get their wristbands, though. You can do this either in the terminal after you check in for the cruise, or at the Club or Lab the first time you take them. They basically confirm your password and the people authorized to pick the kids up and then print wristbands and thread them through the sensors. On our two cruises, the line in the terminal was super long so we waited until later in the afternoon and checked DD in at the club. No line there either time. If your kids don't like wearing the wristband, the CMs at the club will cut them off when you check the kids out and print new wristbands the next time you drop them off.