Originally Posted by Xandrios

Basically what I have done in the past is order the extra cards on their name, but let them be shipped to my own address. Their Flying Blue profile at klm.com or airfrance.com will be upgraded to the new status, and I keep the extra cards home to make sure they don't 'accidentally' use it to purchase stuff.

In fact they wont even find out the card #. Plus the cards will, of course, not be activated (= not usable for payments).