Hugely disagree. Most people can't build a tower which stands at all. In fact if they managed, I would say it's much more "barely standing" than the engineer's.
This is what the engineers claim, and then they tack on a 50% margin of error they don't bother to explain because the business major ghouls would make them remove it if they knew.
Both material factors and load factors are very well explained and grounded, they are not arbitrary. The problem is that they are too technical to explain to a non-engineer.