We too use a cash only account, I had problems with my bank thinking a purchase was fraud and actually closing my DH's account!!! Like two days before our last cruise, if we had not been calling to notify our bank of our travel plans we would not have known that they'd cancelled the DH's card, we had to go to the bank to have a new one made.
Anyways...to keep from having any surprises or embarrassment we always use cash account, because the first time we didn't do this and like two hours after sail away at the bar the sea pass card was declined due to 'lack of funds' ..WTH? WE'd not even used 20$ charge so far... A call to the pursers desk cleared it up, but how embarrassing when we were buying a round of drinks for the new couple we'd been talking with!! We went by and changed to a cash only account after hearing other couples complain about problems their cards. No more trouble so we use cash account on all our cruises. We check our balance when we return to the room each night and can take care of any discrepancies immediately and not days later...we just add more to it if it starts getting low.....never had a problem with using cash $$$:rolleyes: