Board Thread:Support Requests - Designing Your Wiki/@comment-5193807-20130604200122/@comment-10688548-20130604233433

I don't think you can really do much to wrestle such a major change out of being a ToU violation. Certainly not by entrusting the advertisement system into a piece of JavaScript.

This is a Terms of Use violation for more than one reason, the change to the ads system is only one (it is however a fine example). There's also this:

You further agree: Not to intentionally block, remove, or otherwise obstruct the proper functioning and view of advertisements, and/or user interface and functionality by other users, including but not limited to changing or adding javascript or CSS changes to the Service that would prevent the proper display or function of advertisements and/or user interface and functionality;

I like Monobook too, but it's not something that's likely to happen.