I just received an email from Zwift about this active category enforcement.
Actually sounds like exactly what is needed. Especially the game ratcheting back power to the category threshold if you exceed power for too long.
I’m sure there will be some tweeting required. But it’s a start.
Well done Zwift. 
Are you referring to this?
Was this a response from support or a general email sent to all users? I didn’t get any emails…
It was a reply I think I can’t remember what to though
No although the green cones are part of it. I’ll give the short version
On entering you get a warning that you’re entering a lower Cat than you should. You must acknowledge this but get a second warning. You can still enter the lower Cat. However… and this is the good bit IMO.
If you enter a lower Cat having been warned and then exceed the max power of the Cat for a given time you get the “Green cone of shame” your power will then be throttled back into the range for the Category.
I guess you could break away then sit at the top W/Kg having been throttled but on the whole I think it’s a great step forward.
It would of course be nice if they would monitor your account for W/kg readings even for normal rides, although that could be circumvented by using two accounts.