Zune screen cracks - Fact or fiction?

Yesterday Engadget ran a piece about a possible flaw in the design of Microsoft's Zune PMP:

Interesting news on the Zune front: a friendly tipster's buddy works at a Microsoft call center and handles Zune-related issues. Apparently they've received numerous reports of the Zune screen cracking for no apparent reason, after being left charging overnight. Our tipster's friend conjectures that the lithium ion battery -- which resides right behind the top half of the Zune's screen -- is expanding from overheating and putting too much pressure on the screen, causing it to crack.

As you may already know, screen cracks fall outside of Microsoft's warranty, and if this screen cracking due to the battery expanding is real, it leaves owners with a dead Zune and nowhere to go.  Not good.

But how big as problem is this really?  Does it even exist?

My suspicions were raised by the source quoted.  "A friendly tipster's buddy works at a Microsoft call center and handles Zune-related issues" isn't really all that credible a source.  Also, a quick web search doesn't turn up anything about this.  I would imagine that disgruntled Zune owners would have turned to the web as a way to vent their frustrations.  So far a deep web search has turned up nothing.  One commenter on the post on Engadget claims to have experienced an issue similar to this, but without performing an autopsy on the affected Zune it's hard to prove whether this was caused by the battery or not.

Personally, I'm skeptical.  Yes, it might have happened to a small number of users, but my guess is that other factors were at work.  Plenty of devices nowadays incorporate both an LCD screen and a LiIon battery.  Engineers will have factored battery expansion into the design.  Yes, whack too much voltage through the battery or heat it up and it'll expand beyond those tolerances, but then you have a bigger problem on your hands - the battery is being damaged and could rupture.

Anyone here seen this problem with the Zune?  What about other devices?  Have you baked a LiIon battery and bust your device in the process?