I have read this on in a email, but do not have authentic source to verify this claim. This hint is also being circulated on email for long time.
“WHEN A THIEF FORCES YOU TO TAKE MONEY FROM THE ATM, DO NOT ARGUE OR RESIST, YOU MIGHT NOT KNOW WHAT HE OR SHE MIGHT DO TO YOU. WHAT YOU SHOULD DO IS TO PUNCH YOUR PIN IN THE REVERSE, i.e. IF YOUR PIN IS 1254, YOU PUNCH 4521.
THE MOMENT YOU PUNCH IN THE REVERSE, THE MONEY WILL COME OUT BUT WILL BE STUCK INTO THE MACHINE HALF WAY OUT AND IT WILL ALERT THE POLICE WITHOUT THE NOTICE OF THE THIEF.
EVERY ATM HAS IT; IT IS SPECIALLY MADE TO SIGNIFY DANGER AND HELP. NOT EVERYONE IS AWARE OF THIS. FORWARD THIS TO ALL YOUR FRIENDS AND THOSE YOU CARE”
I guess by now all thief must be also knowing this. If you try this and succeed, be aware you will be shot by the thief.