Was never used in EU, at least I don't recall it.
First time I was introduced to this rule was against shk on airtime in 1v1. We played air without caps and the rest with caps and that was like 1-2 years ago.
Also, what about maps like shock? Shock is pretty good map for 1v1, yet capping there is pretty much crucial and adds cool dynamic to the map.
If you want rules which differ to the server settings, you should say so. Just because you think these 'ideas' should be followed as rules don't make them rules. I guess some people 'agreed' on them, but they were never accepted, because I have never seen them written anywhere. That means you can decide on them, but can't use them as an argument if they are broken.
PS:If they are actually written somewhere in the forums as a verified post then I apologize for being wrong.