Do you equip your "backup spotter" with a walkie-talkie?

Truckasaurus has Bluetooth in the radio. DW calls me on the cell phone and has only three basic instructions:

1) Tell me which direction the BACK END of the fifth wheel needs to go (MY left or right).
2) Tell me to STOP when we're in position OR if I'm about to hit something.
3) Don't let herself get run over.

I won't listen to advice, signals, shouts or waves from anyone other than my designated spotter, and she promises not to wander off in pursuit of something shiny.