They monitor your spending habits like a hawk, anything out of the normal they will decline and call you, as they are responsible for unauthorized charges. I recently received a call the day after using my Discover card at a gas station in South Alabama. Someone had tried to charge $600 bucks worth of music downloads.
I get weekly FICO reports stating no unusual activity; cost like five and change a month. My Amex card number was used or the account charged (tried to be) and Amex blocked it. Guess it’s okay although the CC’s I have give me free credit scores once a month but the FICO score is only twice a year.