I've been looking at this all day. We've been amazed in the office - even the guys that don't actually talk about these things. Then I just read it again...
I don't think that has to mean Yahoo are saying they intend to change your campaign without your permission - although obviously some clarification from Yahoo would be in their interests right now. We may prefer to interpret that as saying "If they offer to optimize your campaign AND THEN YOU EXPRESSLY SAY YES, then they will change the campaign."
Just my two pence. Who's going to join me in the campaign for plain legal speak?