What tips the credit card fraud department that a card is being used fraudulently?

Yesterday we got a call telling us that Rick’s card was being used in the Dominican Republic. Well, since we’re in Kansas, that would have been a big flag.

However, a couple of weeks ago I got a call from the fraud department about some purchases made on my card in Nebraska. Well, the charges weren’t mine, but Nebraska is right above Kansas so it wouldn’t be crazy if I had actually been there for some reason.

Neither of us had lost our cards. We physically had them with us.

So…what tips them off?

Can I go to Jamaica and use my card and say it wasn’t me?! :D