A few years ago, this crime-fighting tip circumnavigated the Web: If you were being forced to withdraw money from an ATM, all you had to do was key in your personal identification number -- in reverse -- to call out the police.

According to the electronic rumor mill, the technology was secretly already in place.

Unfortunately, it wasn't true.

Before long the reverse PIN was debunked on Snopes.com and other mythbusting sites as just another urban legend.

But in an age of encryption and just-in-time electronic communication, does it have to be?

That's the question Joe Zingher poses.

Zingher, a retired cop, prosecutor and defense lawyer from a town about halfway between Chicago and Milwaukee, is a one-man lobbying force for using reverse PINs to save lives.

Full disclosure: Zingher is the patent holder on a bit of software he calls SafetyPIN, which he thinks would help our financial institutions easily transform ATMs into emergency call stations.

But what he wants to see first is the compilation of official statistics on ATM-related crime. Zingher thinks the problem goes well beyond the headline-grabbing cases such as Eve Carson, whose ATM card was used before her shooting death in Chapel Hill, or John and Irene Bryant, who were abducted in the North Carolina mountains and killed. The man charged in the Bryants' death and the killing of other hikers was said to have used their ATM cards.

Ed Aycock, vice president of the N.C. Bankers Association, said that while his group follows bank robberies closely, he knows of no statistics on ATM thefts or forced withdrawals.

"But given the incredible number of ATM transactions that occur all over the world every day, I think the number is very, very small," he said.

As for Zingher's SafetyPIN, Aycock sounded just a bit weary. The banking industry official has heard about Zingher's advocacy in three or four other states where it has gained traction -- before opposition from the banking industry stopped it in its tracks.

In other states, the bankers drew on many of the arguments Aycock shared with me.

He said the communication between local ATM machine, bank computer center -- perhaps as far away as Omaha -- and police would probably take too long to aid someone in dire straits.

Aycock said he also fears that the reverse PINs might increase risk of violence. "I have trouble remembering my PIN sometimes," he said. "Imagine trying to remember it in reverse at gunpoint."

Zingher points out that if you've been abducted at gunpoint or knifepoint, you're already under duress. And chances are, things aren't going to end well no matter what. Zingher thinks that if criminals knew they would get their money no matter which order you present your PIN numbers, they might just grab the cash and run -- rather than take a chance the cops were on the way.

Maybe the bankers are right. Maybe this is an impractical idea. The bankers have certainly been successful in crushing it before it ever got off the ground in other states.

But I'd wager the families of Eve Carson and John and Irene Bryant would be willing to give it a try.

This might be one urban legend it would be nice to see come true.