A way to get free points on your credit card?

I read an article today that was about 15 years old. The article was about a man that would buy travellers' cheques with his credit card for around $10,000.00 at the beginning of every month. He accumulated air miles with his card for 10k a month. He would then put the cheques into a high interest account until the end of the month and at the end of the month he took the money out and paid his credit card bill so that no interest would be charged. The man continued to do this until he was caught and the credit card company had to change its policy. Does anyone else have any ideas like this man had? If yes please post them so we can discuss