You would have to be pretty clueless as far as scopes are concerned, to not realize that the vertical turret moves the point of impact vertically, and that the horizontal turret moves the point of impact horizontally. If someone was really that clueless, perhaps they should carry the manual wherever they go.
However, I have actually seen a scope mounted 90 degrees out, and the person couldn't figure out why moving the turret marked U/D actually moved the point of impact left or right. The person that mounted the scope obviously had no clue as to what he was doing.
Actually, mounting a scope that way, i.e. 90 degrees counterclockwise, is an easy solution to the problem of ejected brass striking the windage turret, especially if the turret is the large target type. I've done several that way, and it works well. It also give easy and unobstructed right-handed access to the loading/ejection port. My friends and I had no trouble making adjustments...although, in hindsight, perhaps we were forced to think. A number of years ago, at least one manufacturer (I think it was Simmons) manufactured a tactical scope designed to be mounted in this position, i.e. windage turret on the left side of the gun, elevation in the traditional position. I never saw one, but now I wonder how the turrets were marked...the potential problems were HUGE!