[BattleFlag]

I thought when you use a "debit card" as a credit card the zip code is used as a security measure. If a (physical) card is stolen, not having the associated zip code would not allow it to be used.

I don't recall being asked for it for debit card transactions where a PIN is provided.

Guess I was wrong about this.

[Rio]

My limited understanding of this is that, when you are present to sign the credit slip, then no other confirmation is required. If you are shopping via phone or web, then a further piece of information is needed to confirm that you actually are in possession of the card. That information can be ZIP or the CVR code from the reverse of the card.

I’ve gotten rejects when using a credit card online because I used a ZIP code that didn’t match the billing address for the card.