I guess you don't need a free bumper then. That's good news.Well, first we would need some evidence they exist.
Then we would need to understand how they became so retarded as to not return a product with which they are having issues, or at least seek assistance.
The problem is that Apple already reserved $175 million for free bumpers/cases, just to keep its users happy. People who might have otherwise returned their iPhone 4. I guess these people are all retarded in your book, but for me these are potential unhappy customers.
Now wait for another problem to appear, and the first thing people do is say: "I already had to use a bumper, and now this or that...". That's how the human brain works.