What is the purpose behind this new regulation requiring that "Debit Card" be printed on check cards when they can be processed as a Credit OR Debit. Probably a dumb question but enlighten me anyway! (I have heard that some places are reluctant to take the cards when they see the "debit" label and they know they only take "credit" cards)

The Debit Card notation on all cards came out of the settlement between Wal Mart and the card companies - Wal Mart wanted to know if the card was a Debit Card so it's use would be as a Debit Card resulting in lower processing costs to Wal Mart.

Paragon is correct. Originally the debit cards with the MC/V branding had a selling point of "it looks like a credit card, but acts like a check". Ironically that is what bit them in the backside.

Wal Mart contended that the fee on a credit card and a debit card should differ. There is no credit risk on the debit card to justify the merchant's fee. Reg. E / zero liability rules aside, this is true. SO they want to now more clearly differentiate the two products.