We took our walkie-talkies but didn't use them too much. When we did use them the reception was fine. I can't ever remember them being out of range. I can't ever remember needing them too much though either???

(this is one of the times I didn't want my kids to find me

) Actually as far as my kids.... I had an update it seemed from everyone we knew- about my kids. It was great. In our group of Disers we had the Oldest more unsupervised kids. I always knew where they were all the time. The other adults always filled us in.
The refillable mugs- Yes you have to lug them with you wherever you go. Each stateroom is equipped with a MUG WASHER!! It is in the corner of the bathroom. You lift the lid, insert mug and HOLD ON TIGHT!!! If you do not hear a really loud noise and Air rushing past your ears it isn't working right. (really Bob- I'm just kidding) We didn't buy mugs. We brought a case of Diet Pepsi on board. We are thinking about buying 1 this year and letting mutt and jeff split it. Sodas are free at dinner.
DH did invest in the ESPN beer mug. It was 22oz glass mug. They exchanged it each time he turned it in for a refill and gave him a frosted one. The Soda mugs you have to track...so a marker would probably be in order.
We ate at HRC last year in St. Thomas. Well we ate munchies at lunchtime and had a drink and then dinner on board. You can also shop and drink, go back on-board and drop of your purchases, eat and go back out again.
I will probably stay away from food and/or drinks in Cozumel. I've heard a lot about people getting sick. We may take Bottled water on the ship this time, to make sure we have plenty.
smiles Patty