The only distance that counts is 15 feet. That's the bench mark for scale judging.
In literal terms it's nearly impossible to Duplicate the full scale in model form. We can get pretty close but mechanical lines etc really don't scale down as we might like them to. Molecules are what they are, a fixed size.

So what we can do is to do a bit of "show biz". We present an "impression" of the full scale plane. The idea is have the judge see the plane as it might have appeared in real life.

I will agree that a lot of models are over weatherd. I don't think this is done on purpose but rather the result of a lack skill and research.