Visual vs HTML editing for pages vs posts?

Does anyone know of a way that I can force wordpress to by default only allow editing of *pages* in HTML and force the default editing mode for *posts* to Visual?

The reason is that wordpress does weird stuff (changes the code) when you switch modes from visual to html on *pages*. It throws in its own formatting and this could potentially destroy my entire site.

I have a writer who updates the posts, and I don’t need anyone accidentally saving over a page with WP’s forcing of changing the code between visual/html modes.

Hopefully someone knows what I’m talking about… Anyone using WP as a CMS should.

Note: I am aware that you can disable the visual editor entirely, but then you have to format posts by hand, the people I have writing the posts are not technical enough to add div and other css/html tags by hand so I really need the visual editor ONLY on posts.