Wal-Mart Training Tape in Focus in Debit Case

A Wal-Mart employee-training videotape may prove a key piece of evidence for Visa and MasterCard in the upcoming trial over debit card rules, which had a dress rehearsal of sorts on Friday.

The tape shows the difference between Visa and MasterCard debit cards and other types — and instructs cashiers to encourage customers to use the other types.