Any child that is going to take part in the kids program must be checked in. They need emergency info. You can do this on line as part of the on line check in process and then just check in to confirm that they have e very thing they need.
You can do this at the port or once on board. I know iot is a must for the Club and the lab. Not sure how it works for the older kids. The younger one will need to wear the band that has the scanner chip to ID the child any time trhey are in the club. That is part of what you get when you complete the check in process in person.
Do not know if this is the info you were seeking but I hope it helps.