Just back from the WBPC cruise on the Magic. I used my MB+ almost exclusively. The exceptions were Palo brunch and dinner, since having it on my wrist with the long-sleeved shirt I was wearing would have made it awkward to give to the server when taking care of the charges. DW used either KTTW card on a lanyard or MB+, depending on what other wrist decoration was being worn at the time.
I never bothered to charge my MB+. It worked fine for opening the stateroom door and for charging. I was asked for card or band to process charges pretty consistently, although our assistant server forgot one night when I ordered a bottle of wine from my wine package. Those transactions after the initial purchase involve a $0.00 bill, since it’s just used to track the number of bottles that have been consumed. I always include additional gratuity for our serving team on the initial purchase, so that’s been taken care of already. Charges then appear on the in-room account summary on the TV as $0.00, but never make it to the room charges information in the app or the final account folio PDF. It’s actually interesting to monitor the account information on the room TV. The 18% autogratuities appear as a separate line item for each transaction, as do any added gratuity that I include when signing the bill. Even the Palo gratuities are broken out into separate lines, apparently for the split between the server and whoever else gets a small cut from those. We also had a popcorn bucket that I refilled almost daily. That appeared as two line items, $1.75 for the refill itself and $0.31 for the autogratuity (I would have expected them to round up to $0.32, but no). Folio just shows a $2.06 charge each time (the crew member at the popcorn cart outside the Buena Vista movie theater filled the bucket with popped corn and scanned my MB+; didn’t even ask for a signature on the iPad).