When I was a trainer I bought a remote controlled tractor trailer. Knowing that when I first started out one of the issues I had was spatial relationships and how to interpret what was going on in my mirrors. The RC truck helped many a trainee quickly understand the fundamentals of tight quarter movement, whether going forward or backward. I could set up a dozen different nasty backing situations and let the trainee and other newbies watching in the terminal driver's lounge have a go at it. Sometimes folks would chime in with real world "impossible" backs. Then we could all analyze different ways to get the job done. Having that RC rig was like looking down from a drone. Hecklers were encouraged.
You never when a Child might walk behind a vehicle...Just because it's loading docks or wherever...Boys will Be Boys..They might be chasing a Cat or a Ball.. .
A few years ago a driver opened his doors and while walking back to the truck a bear climbed in the trailer, it scared the peewaddle out of the forklift operator. lol