They routinely track purchases and flag accounts with suspicious charges. (creditdonkey.com)
Then two days later I received a phone call from Chase, informing me they had denied a number of suspicious charges happening on the east coast (I was in California at the time). (travelcodex.com)
They have robust anti-fraud departments and if suspicious charges start appearing on your card, they will notify you and perhaps even shut down your card until the concerns are resolved. (creditcards.com)