>If the wrong person did it I could see this leading to people getting hurt (falling off the catwalk) or damage to cars (improper fastening)

I really don't like seeing this sort of whatifism whenever a story about somebody doing something that is not their day job comes up. It's amazing it's still considered safe to file your own taxes. The dude had the skills and he did the job and did it well. Hand wringing over what-ifs adds nothing to the discussion.