Left unchecked, Yes.
Without offering me an option it.
-- Took over default ownership of playing my MP3s.
-- Took over default ownership of playing .flacs, even though it was incapable of playing .flacs.
-- Loaded itself every time I plugged in my MP3 player (not an iPod.)
-- Somehow broke streaming MP3s to my sound system via TVersity. I know this one makes no sense but it all worked again when it was no longer my default player.
-- Keeps telling me I need to update it but insist on including updates of software I don't want bundled with it. I have to manually go to their site to update without the extras.
-- Every song in my Softsqueeze library was showing up twice until I turned off iTunes compatibility.

All these things were easily resolved but it was a big PITA when my wife won a Shuffle at work.

To be fair, it's a great, simple to use solution for most iPod users who only use the one player and nothing else. It just doesn't play nice with the rest of the world.

With great power comes Awesome irresponsibility.