in europe most people don't use have a creditcard, but a ATM card. Which not only allow use to get money out of machines, but also pay in store's. It's PIN code protected. So i doubt anybody would kill you for a creditcard in europe.

I really don't know what i would do, you could draw a legal-to carry-defence-spray. But i'm not so sure about the legal bit wenn you are going to school with it.