...just one more point: sometimes, checkbooks are actually tied to
significant "lines of credit". For example, a $20,000 line of credit from a
major bank, with checking privileges. In this case, he may not have had the
money to pay, and may have been borrowing it via a line of credit "cheque".
Sometimes, these lines of credit may have an attractive interest rate,
making the customer prefer them over using a high interest credit card...

Tom