Ahhh:
http://channel9.msdn.com/ShowPost.aspx?PostID=311787

This doesn't ring true:

The reason we’re able to offer Express for free and even let developers build commercial applications with Express is because we limit 3rd party extensibility of Express, specifically by removing support macros, add-ins, and VSIP packages.

So stop distributing Express. Or give away the full product.

Piss or get off the pot.