How about if your cell phone came to the rescue if you locked your keys in the car?

Or if it could identify a stranger approaching your car?

As cell phones become more commonplace, so do the tall tales and myths that go along with them.

But experts said some of those promises could be downright dangerous for those who might depend on them.

Craig Fowler of Verizon explained one popular myth.

"A woman ... saw someone who was impersonating -- or at least she thought was impersonating -- a police officer walking up to her car. So, she dialed #77 and got connected to some mystical agency that was going to identify who this person was."

Another rumor is a "worldwide emergency cell phone number." The claim states if you're out of your coverage area and have an emergency, simply dial 112 and you'll be patched to an emergency dispatcher.

The truth is, Fowler said, neither of these claims are true.

"Make sure 911 is the number people are dialing," he said.

Another rumor claims that if a driver has keyless entry and locks the keys in the car, the driver can call someone at home on another cell phone. The person at home can put the spare set of keys up to the cell phone and hit the unlock button while the driver points the cell phone at the car. The signal supposedly carries through the phones and unlocks the car.

Sounds too good to be true? It is.

"Those remotes for your car work on radio frequency, you've got to be within a certain distance of your car to transmit it. There's no magical power that's going to send that from your house to unlock your car," Fowler said.

How about this one: There's a hidden battery power in cell phones. If the battery is low, simply hit *3370# and the cell phone battery will get a 50 percent power boost until it's charged again.

Nope.

"I can confidently tell you that one is a lie. The battery that you have on your phone is the only way you can see what kind of voltage you have in your phone," Fowler said.

Despite the many false rumors and unfounded claims, Fowler said there are some numbers that actually can help cell phone users. On a Verizon phone, pressing #MIN will tell customers how many minutes are left on the plan for that month, or #BAL will tell customers their balance due.

Fowler said the bottom line to stay safe is to always keep cell phones charged and dial 911 for emergencies.