Funny, it seems like this number keeps going up. At first people said "You're OCD if you return 3 iPads.". Then it was 5 or 6. (I finally got a decent one after 5). Yesterday it was 12. Today it's 15.
Seems to me that as long as there are people who are getting good ones and people getting bad ones, the people getting bad ones will continue trying to find a good one.
Of course, its subjective. Do you think the AVERAGE Apple consumer is going to return an iPad because of one or even a few dead pixels. I seriously doubt it. It's all in your head dude.
I think it's the same line of thinking that leads many Americans to sterilize their homes with harsh illness causing chemicals due to an irrational belief that microscopic germs are plotting against them.