Ship the version with it in, but disabled. Have it un-disable sporadically. When told that they are breaking the agreement, complain, But WMP is part of the operating system. We can't really remove it without breaking the machine. We do our best to hide it from the user. The disabled version is, other that the missing functionality, not worse than the usual version...

Maybe this will fly, maybe it won't. But Microsoft has decades of experience fighting anti-trust rulings in exactly this matter, why change a winning strategy? (And IIRC, they have used this kind of technique in the EU before. About 10 years ago, in fact.)

Cheers,
Ben