Quote Originally Posted by Darkobra View Post
It's mainly a thing to cover Square. So if you choose to download anything like that and there's technical issues or viruses, Square will simply tell you it's against their terms to even use them so your help will be next to nothing. I doubt they'll actually ban someone using them.
It's deeper than that, their choice to not allow addons was due to the toxic environment found in games like WOW that had them. So the designed the game in a way as to not need end game addons. They then banned the use of aftermarket mods, both for the legal and to avoid toxic game elements.

As to banning the use, they will if you tell them you use them. As SE is really on the ball when it comes to enforcing rule breaks when they know about it, and can prove it.