Whether or not they have a car phone is not even an issue. It's not something that would even cross my mind.

We live in a very dangerous world where criminals / bad people use various tricks to get you to stop for them. You may see what looks like a pregnant woman supposedly stranded at the side of the road with a broken down car and may decide to stop to help. You realize too late that it is a trap and her friends are waiting at the side of the road to jump you. They may rob you, rape you, kidnap you or kill you. It doesn't matter if you are male or female, it is still dangerous.

Just as hitchhiking with strangers is dangerous, picking up strange people is just as dangerous.

Polytechnic Institute of NYU safety tips for students includes: -

"Do not stop for stranded motorists. Instead, use your cell phone or go to the nearest telephone booth and call the police for assistance."

"Do not open your window if someone approaches your vehicle to ask for directions, the time, etc. Keep the door locked."

http://archive.poly.edu/studentcitizenship/safety/index.php

There are other such warnings out there.

As human beings we want to help but we need to think about our own safety and the safety of other people (friends / family) that we may have in the car with us first.