I got this information and never knew about it.
I received this and thought it was worth sending on......hope none of you will ever have to use it!
Pin numbers in Reverse

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.