@steveb, we may be in more agreement than it seems on the surface. I would boil down my caution to one simple case - if the site is already getting Google traffic, then modifying your main navigation to include a keyword link to the home page can run a risk.
A keyword link the body copy of a strong internal page is a good idea. A footer navigation link might also work well. And WHAT keyword you're trying to rank for may be a much bigger factor than any of those I mentioned so far.
The reports I've seen of trouble were a lot more that 1 time in a zillion. Although they did not happen on my sites, I also never tried to retrofit a keyword link into the main navigation.
To offer a balanced view of this situation, I felt it was only right to pass on some cautionary information. Some people reading this thread may well go overboard without that word of caution.
And if we still disagree? well, that's diversity of opinion and experience for you. I've got no problem being on the other side of this issue because I have sites where it works well - even in the main menu.