It is a violation to make ID a condition of accepting Visa at all. It is not a violation to ask for ID from specific customers, regardless of whether the card is signed or not. It says this very clearly in the "Card Acceptance Guidelines for Visa Merchants" booklet. The closest they get to forbidding it is a recommendation that you don't make it part of your standard procedure as, and I quote, "it can slow down a sale and annoy the customer".

In the case of a suspicious transaction, the merchant is also supposed to call Visa for a "Code 10 Authorization". One of the things Visa may do is instruct you to check the customer's ID.

If a store asks you for your ID, calling up Visa to report a violation won't do you any good as they haven't violated anything. As far as your jurisdiction punt, we're talking about a product intended (and only really usable) for the US.