You might want to read this:

http://blogs.zdnet.com/Bott/?p=84

Sure, they've turned it off for now, but the rumor is that's not going to be the case in the future.

Of course, since you're getting the updates anyway, you're using a legit copy. BUT, if I read the article correctly if you turn it off in the future or remove it, you're not going to like the outcome.