Another Credit Card Story

I suppose, in fairness, I should tell another credit card story. A few days ago, my husband got a phone call from the credit card company that has our VISA credit cards (different from the one I complained about on Sunday, May 28, 2006 in another post). It seems that there were some strange charges on my account, which has a different number from his, and they wanted to check if they were really mine. I am not sure what made them think the charges were strange. I don't shop at Walmart, but I do buy things online from various stores - what flagged the Walmart charge as suspicious? There were 3 other charges also flagged as suspicious and I still don't know what triggered the suspicious flag. I guess I am grateful, though. I will be even more grateful if I don't have to pay for the suspicious charges.