Losing your wallet is a lousy experience with a huge number of headaches and concerns. Here is a very simple, handy and extremely sneaky tip to, at least somewhat protect your credit cards if your wallet is lost.
On a small piece of paper, write 3 random fake PIN numbers. Put this paper in your wallet where you have credit or bank cards. If a thief DOES come into possession of your wallet, they will most likely attempt to use those numbers causing your card to become locked and useless.
Simple and effective.