First of all, I just THINK, I'm not saying is true, it has only happened once on me, I'm trying it tomorrow again.
Just to tell you guys, If you have configured your Xbox to play the disc when you turn it on, if you click on the "open tray button" On the Xbox, in the moment it begins to read it,, you get a message saying it's unreadable, I don't know if it's a bug or just normal because of interrumpting the function.
And I say it again, it has only happened once, but my Xbox is First-Generation, don't know if it can happen again, or if it can happen in the actual consoles. Hope someone can help me to figure this out. :)