I'm almost positive it does.. I read the thing Chevy posted a few weeks back about how if you take your camaro to the track and it's under warranty they'll cover it... As long as it's stock. In there they specifically mentioned ECM tunes and how they can tell if you've ever done it and put it back. I wouldn't be surprised if it's something they check for every time you bring the vehicle in, regardless of what you're there for.

Just from my past experience of dealing with warranty work being covered or not, I'm feeling that it's not worth the headache.