From https://sites.google.com/site/webmasterhelpforum/en/faq--webmaster-tools :

Q: Why do my Webmaster Tools stats show common phrases such as "buy now" that are not directly related to my site?

A: While some common words and phrases are filtered by Webmaster Tools, there may be some that you use which are not. Having these words or phrases listed in your Webmaster Tools account does not mean that our algorithms will view your site as being only relevant for those keywords. While Webmaster Tools mostly counts the occurences of words on your site, our web-search algorithms use well over 200 other factors for crawling, indexing and ranking. In other words: don't worry if you see keywords like this listed in your Webmaster Tools account.

I couldn't find a more detailed estimation of the impact of such keywords, but we should consider the option of just ignoring the issue. Especially since according to this the only effective options are JavaScript or frames tricks, both of which would make LW significantly more annoying or slow to use.

taryneast's idea of using CSS to pretend-shove the opening blurb to the bottom of the page could be rather painless, though.