@ Work: What's wrong with this scenario?

I work on jobsites, and heavy equipment move in and out of the place all the time. Sometimes, because of the sheer traffic, and also the limited visibility of crane operators and truck drivers, we have signal men.

In a nutshell: The operators only drive the equipment, and signal men are their eyes. They give hand signals to the operators on where/how to move, and make sure nothing hits......

I spotted this on site today:
The bl***y signal man was talking on the phone while trying to get the truck to back up/reverse!! Its almost like asking a big, fat and blind-folded elephant to walk a tight rope and not fall over. Bad idea!