When my card was blocked, the CSR told me it was done completely at random, not as a result of a fraudulent or out-of-place transaction. They just wanted to confirm details of my credit report and decided to block my card until I returned their call. I wrote about this before, but to make a long story short, I made the rude CSR angry because I wouldn't provide him with numbers from a MasterCard I hold with another bank. He wouldn't let me speak with a supervisor, then "discovered" a suspicious attempted transaction, cancelled my card, and sent me a replacement. I'm keeping the card for now, but will almost certainly cancel before it's renewed for another year.