URBAN LEGEND: Put Your Pin # in Reverse if You're Held Up at an ATM

The claim:

If you should ever be forced by a robber to withdraw money from an ATM machine, you can notify the police by entering your Pin # in reverse.  For example if your pin number is 1234 then you would put in 4321. The ATM recognizes that your pin number is backwards from the ATM card you placed in the machine.  The machine will still give you the money you requested, but unknown to the robber, the police will be immediately dispatched to help you.  This information was recently broadcast on FOX TV and it states that it is seldom used because people don't know it exists.

The

The truth, according to Snopes.com:

This does NOT summons to police.  A Chicago businessman patented a similar system, but he was unsuccessful in getting banks to purchase it.  Bills that would mandate panic systems such as this have been introduced in several states, but none have been passed.  For the complete story, click here.

So,

If you’re held up at an ATM, give up the money and keep yourself safe.  Money can be replaced.  You cannot.