I first did a blog on Do you Protect Your PIN at ATM on this site last winter.  In it I stated:

"The most common ways that criminals obtain a PIN at an ATM are by looking over your shoulder (defeated by covering your PIN), by using spy or micro cameras (also defeated by covering your PIN) and by using a false overlay over the PIN pad.

It should be second nature to cover your PIN at an ATM, just as you don’t typically hold your wallet wide open when removing notes, so that others can see how much is in it."

Sure criminals can also compromise your PIN by PIN Pad overlays of one form or another, but using cameras or looking over your shoulder remain the most common methods.  Why do they need the PIN?  Because if they have it they have a chance of making illegal cash withdrawals using trapped or counterfeit cards (as well as illegal payment transactions). 

The European ATM Security Team (EAST) have just put a video on their website showing seized criminal video footage.  The criminals have already switched the camera on and so you see them fixing it above the ATM PIN pad, before installing their skimming device over the ATM card reader throat.  The next thing you see are ATM users carrying out transactions without covering their PINs - can you work out their PINs?  If you play the video a few times you'll be able to. 

Then you see some ATM users covering their PINs.  What you see is what the criminals see, if you can't see the PINs, neither can they. 

In this case a picture or image really is worth a thousand words.  You can watch the streamed video on the Cardholder Security Tips page of the EAST website, and also download a copy if the stream doesn't work.

If you don't routinely cover your PIN when making an ATM transaction, you might start after watching it!