The last time I had one, some jerk in Asia did hundreds of small transactions using my credit card number and only I noticed it. US Bank didn’t catch it at all. I had to contact them and then they sent me a gigantic document with every single transaction that I had to go through, sign them all or something and go down to the branch and do a bunch of $@&+ there. The guy just ran numbers (they said) and found mine. If I hadn’t thought to check my credit card balance online it would have not been noticed until he maxed it out, probably.