So, this is not suspicious
Not sure I totally agree with you here. Having driven some large vehicles in my time, I would always use a "spotter" as a safety percaution while backing the truck up.
To me, asking for a spotter is a bit different than not want to know how to back a rig up at all.
Not sure there is a "plot" involved here, but better safe than sorry...and with the expired visa, send him home.
I needed to know how to back up for a simple operators license. I'm pretty sure backing up is required to get a CDL.
My drivers used to call these concrete cowboys "fruit pickers" and we really didn't want them backing to our doors after losing a couple of curtains and a bollard.
We agree on the bottom line.