Some guy was telling me its a known failure mode and he's had two do it. I've NEVER seen or heard of that happening. And considering anodized aluminum doesn't conduct electricity, I don't see how it could.
I think he's full of the shiat myself. I've seen pictures (as I'm sure everyone else here has) of a MBP that was run over by a car and still worked.
He said if the dent is big enough, it can cause the boards to rub through the anodizing and cause the short, again I called BS as you can't really 'rub through' anodizing...it's not paint.