This poll is completely meaningless in terms of establishing any kind of failure rate. Most people who own a Zebralight will never see it.
Besides, if I got a Zebralight yesterday, and it was DOA, and I voted "yes, I've had a failure", there would be no mention of my three perfect ones.
By the same token, if all three of mine had failed, they would only count as one failure.
It's obvious that the incidence of failure, whatever it may actually be, is way to freaking high, regardless, but let's not try to make this into something it isn't.