O.K. here is some interesting information....

The banks blocking said transactions apparently has nothing to do with the Govt. whatsoever!

It is entirely the bank's discretion.

There are two reasons that they block the cards.

1. Identity Fraud

2. Bad debts due to gambling.

Here is an example:

A friend of mine always paid his ANZ credit card on time and was never over his limit.
He did however, withdraw $1,000 at the local Casino.

Two months later, he was declined a limit increase because he had made a withdrawal at the casino and was considered a possible credit risk.