At the first, there is the game with standard rules.
Then there is some community.
Comunity changes rules. Here the comunity splits into majority and minority.
Minority does not accept changed rules as majority does.
Majority push away minority. Majority accept rules which recognizes as allowed rules.
Now there are rules.
Simple answer. What majority wants to be clear, majority makes it clear. Majority > minority. Majority can use some explanations which makes it excuse.
Minority, halfnoobs, and noobs can sucks dicks.
I know about almost (X) "some" players, they playing tournaments that they used modified content, not just skins. A lot of people knows about modification and acts like they do not. I and some guys around me even know about 1 guy and 1 clan that uploaded one not very clear content that is not really allowed. They are not banned.
SKins are not cheating for me anyway.