Bottom line; With a credit card, the bank has assumed the risk on the consumers behalf.... unsecured credit cards are flexible, and the creditor will catch up with its client sooner or later, with its own calculated strategery.
Debit cards, are honest. If it aint there, it aint there. Good business IMHO. (99% of my own purchases are with debit also).
So, when you check in to a hotel, the automated system ads a percentage to what the room rate is, for incidentals. (food, calls, pron, etc). Same with a CC. Then it sends that number to the bank for instant authorization. For a presumed 4 nights stay, then ad say 15-35% for taxes and incidentals, and it's easy to see an unrealistic number being authorized. Standard hotel policy. (you should see the number when its for a 60+ night stay!)
With the CC, the preliminary number floats around within the credit limit and the banks policy. With a debit card, the funds are locked down solid, with zero flexibility. Honest, remember?
So, lets say the traveler checks out early, or decides to pay cash or check at checkout time. That authorization takes some time to clear. That part of the procedure is NOT instant. Yes, the hotel sends it instantly, and the banks policy is likely instant. But the clearing house does not. There's a lag between the time the funds are released in theory, and when they are released physically, likely for the purpose of protecting the bank and merchant from the indecisiveness of the consumer. (customers change their minds a lot).
So, the customer decides to pay cash at checkout, and then goes to the gas station to fill his tank with his debit card. BUT, the authorization hasn't cleared yet...so guess what.... DENIED No MO' Money!
Sadly, this will likely happen during a three day holiday weekend, to a 300 lb logger traveling with his wife and newborn, and who has no patience for his banks phone recordings, and even less patience for a hotels explanation of all this.
This ladies and gentlemen, is one of the joys I look forward to in the service industry.
Anyhow, the power outage, and the situation described above, is likely what it's all about. Don't hurt 'em too badly Hammer.