The "problem" of companies holding debit cards and pin numbers is well known to the banking industry. A few years ago I was working for a company that organised a charter for a mob of about 30 quite high ranking people from the banking and finance industry from Alice Springs to Aryeonga so they could see the practice in action.
Very thoughtful mob on their return as the vast majority had never been to Central Australia before let alone an Aboriginal community. I think some thought a remote area was south western suburbs of Sydney.
I worked for a company in 2000 that kept debit cards and pin numbers for unpaid charters. Every morning we would swipe the card until the debt was paid and then return it when next we saw the passenger. I was told of one company whose owner had a card reader at his house and would swipe them when he woke so as to beat any person who may have had another card. The practice was common. We only used it to pay for charter flights though.