What credit-card issuers stress is for your convenience might end up inconveniencing you—to put it mildly. Credit cards that are sent to replace your expiring ones often don’t have to be activated by you and the credit-card company before they can be used for purchases of low value. This is explained as being a rule that exists for your convenience, contends Ben Woolsey of Creditcards.com. Scott Stevenson of EliminateIDTheft says even some new cardholders get buying privileges without activation. But that means that if your non-activated card is lost or stolen, it can be used.