Crashing MBA w/lid closed?

I have been having some very weird intermittent problems with my MBA (description below). Sometimes, when the lid is closed, it will chime and reboot. Never happens with the lid open/not sleeping. Sometimes it's right away and other times it can be after a long sleep.

I can't actually tell whether this is a software issue or a hardware issue, and it seems difficult to reproduce reliably. It only seems to crash when VMware Fusion 5.0.2 running, although it doesn't matter whether a guest is running, suspended, or not even open. I haven't seen a crash with Fusion *not* running. Usually nothing else is running (except of course Finder).

But OTOH, it seems like it could be a hardware problem because if I touch or gently squeeze the MBA at the back near the hinge, I can sometimes get it to crash. Lid closed, touch or pinch the back hinge, and you'll hear the chime, and if you open the lid it will have restarted. It doesn't seem like it's related to the power button at the upper right because if I pinch the MBA closer to where the button would be, it doesn't crash.

I have an open issue with VMware on this, but they can't figure it out, and as I say, it may not even be a software issue, except that I can't crash it if Fusion isn't running (yet 😉).

I'm totally perplexed.