Adventure Ocean - How did kids contact us

We'll have a 9, 8, and 3 year old when we cruise on Symphony of the Seas next year. How will they get in contact with us if they need something? If my 3 year old gets fussy, do they contact us? We have thought about leaving him in AO to do a 2-3 hour activity with our older ones at one of the ports. Is that allowed? Thank you!

You will find more expertise on this subject if you look over on the RCI board, here:

https://boards.cruisecritic.com/forumdisplay.php?f=83

Thank you!