Accepted interpretation or just good and courteous policy?

[Palantir30]

In
http://www.belegarth.com/board/viewtopic.php?t=10507
one finds:

I ho(p)e Nanga didn't die from that flat.

My question is whether it is explicitly stated in the BOW or it is universal herald opinion that this is true or if it is just good and courteous policy?

I have always played like this, that the flat edge of the blade is NOT a striking surface and thus cannot score injury since it is essentially incidental padding.

But I just wanted a quick reality check, is this herald-enforceable (if it's a situation worthy of bothering with that) or is it another of the courteous behaviors that you're free to use yourself but cannot expect from others or hold them to? I was unable to find a specifically applicable clause in the BoW, because this is quite a specific detail.

[Kyrax]

Both, as long as you understand that the weapon is a sword and not an interestingly rectangular shaped club. When people know that they've flatted, a good (and honorable) fighter will tell their opponent not to take it. I've called it on myself or told someone to get up when I had hit them with the incidental padding of my glaive.

It is a fine point, but one that people who take this game seriously do pay attention to. It is not a rule per-se in the BOW but falls under the general common sense provisions.