I think the OP is referencing the solo diving DMs and instructors often do to set up for a class. When I was a DMC, I was solo when doing my mapping project and because I was spending so much time underwater (I was setting a line between objects to get accurate compass readings), so I was outfitted for solo diving with a pony, cutting tools, etc., pretty much what was needed to get out of dodge. I had no course for this.
When I teach open water, I am there an hour before my students setting up a 44 lb. claw hammer to secure my dive platform and a small lift bag underwater on the other end of the rope to account for the tide going in and out. I don't have redundant air as the surface is so close. When I teach navigation, I set up 100 feet of line at around 20 feet (one end to the chain of an existing buoy and the other with a buoy I bring). So, I am task loaded, not diving for fun, but have to have the SA to ensure I don't get entangled and drown.
Now this may or may not be the experience of other instructors but given that the OP taught in the same waters as me, I'm guessing it is. I cannot speak for other regions of the world.
Risk of litigation trumps all however. It doesn't matter for insurance policies if someone has the experience. It matters if they have the card.