When is it taboo to pass down martial arts without explicit permission?

[Tian Chixing's Chef]

So imagine that you were a Shaolin lay disciple. You learned the Wood Ignition Chop from Xuan Ku, making you the elder martial brother of Xiao Feng. Then you start boasting to your hometown neighbors and relatives. Are you allowed to pass on this skill to your child?

Or do you have to bring the kid to Shaolin, then he has to learn those skills through an official channel, and you can only help train him afterwards?

It seems like it is taboo for lay disciplines to directly teach without the new student taking a formal monk teacher first. Otherwise Lin Yuantu could have taught some Shaolin internal power method to his Lin adopted child. Imagine the Lin family with the poor external 72 Bixie Jianfa but backed by orthodox Shaolin internal power, they could put up a better fight against Yu Canghai.

Here is a blatant case of seemingly passing down a skill without permission:

Guo Jing taught Guo Xiang 1 Yang Zhi and she used it against the Shaolin monk who tried to guess her martial arts background. Did Guo Jing have authorization to teach her 1 Yang Zhi?

Would it have been taboo for Guo Xiang to teach 1 Yang Zhi to her Emei school?

What if Guo Xiang taught Divine Finger Snap or Peach Blossom martial arts to the Emei school? Huang Yaoshi is the unconventional type, and I'm sure he would have been very proud of his granddaughter. So instead of those wondrous skills, which include palm skills, sword skills and the Divine Finger Snap being lost, why not let his descendant teach it?

[Western Eccentric]

Well Guo Jing never learn Yiyang Zhi so Yideng or maybe Wu Santong should be the one who taught Guo Xiang Yiyang Zhi..

[Mandred Skavenslayer]

Direct skills especially signature moves would require specific permission, sometimes even by the schools/family elders and not just the direct sifu.

However, skills invented by the individual, even if they are inspired by the original school/family should be alright to teach without permission. As for GX, she did encounter Yideng as well so she might have got 1 Yang Finger directly from him.

So keeping to the above, GX could not directly teach those skills to others, but could use them as inspiration to create new skills akin to the original and teach it at her discretion.

[Ken Cheng]

I was under the impression that Gwok Seung learned 1 Yeung Finger Technique from the Mo Brothers.

[Western Eccentric]

I was under the impression that Gwok Seung learned 1 Yeung Finger Technique from the Mo Brothers.

I think even end-ROCH Wu brothers not as good as their father 40 years ago so hard to believe if Guo Xiang learn Yiyang Zhi from them since she have a lot of "wildcard" not only from her family kungfu but also from their allies like Yang couple or Zhou couple even from lesser experts like Zhu Zhiliu so why you learn from junior if you have access from the senior/experts itself..

[Western Eccentric]

Direct skills especially signature moves would require specific permission, sometimes even by the schools/family elders and not just the direct sifu.

However, skills invented by the individual, even if they are inspired by the original school/family should be alright to teach without permission. As for GX, she did encounter Yideng as well so she might have got 1 Yang Finger directly from him.

So keeping to the above, GX could not directly teach those skills to others, but could use them as inspiration to create new skills akin to the original and teach it at her discretion.

Absoutely true..