Curious what you mean by "dummy" cards? I like this idea for European travel.
Cards which at a quick glance could pass for credit cards. Do not use expired real Visa/Mastercard/Amex credit cards which are still active; they can still be defrauded or used for identity theft. I use a couple old regional department store credit cards from stores that no longer exist (they wouldn't know that overseas) and are no longer on my credit history up front, then pack a couple old (do not use your current) hotel key cards behind it for thickness. Make sure the cash is reasonably visible so they don't immediately think you're tossing them a fake.
Originally Posted by bltkmt
Another good tip is to have a low limit credit card that you only really use while travelling. Limits the damage they can do if you card is lost or defrauded.