The Future of SE Advertising

With the advent of US, I am wondering what the evolution of paid ads will look like. It seems to me that US will change the visibility of paid ads in the future, since it alters SERs. Second search and US capability are going to make it commonplace for the SE to show the results for the requested search, as well as the results for a more useful search - which, hypothetically, the user would have requested in the first place, if they knew what they were doing. Since we're speaking hypothetically, my hypothesis is that, once US and Second search get going, the SE will start to show ads for the keywords that are deemed "more relevant." Why wouldn't they? If I've got a phrase that I think the user is going to find more useful than the phrase he requested, why wouldn't I display more useful ads, if I thought I could?

Just to make sure everyone understands what I'm talking about, the fallout from this would be that the advertisers who bought keywords matching the less helpful phrase would receive lower placement than the ones who bought keywords matching the more helpful phrase. So, if I, the user, search for [travel northeast], and the SE thinks that a search for [airfares new england] would be more useful, then the ads shown would match [discount airfares...], instead of [travel northeast]. The ads that are most likely lucrative for the SE and the advertiser would be the ones judged as most relevant, in my opinion, meaning that the ads matching the Second Search - not the intended search - will receive higher placement.

Of course, that's just my opinion. You are free to disagree.