Yes, possibly the manufacturer would work with you, but in my case, on my previous phone (dare I say it? Instinct) the touch screen was totaly frozen. Couldn't make or answer any calls. So, while I wait for the manufacturer to send me a working one, what do I use for a phone?
In its defense, Sprint did offer to exchange it on the spot for me for $50. Which I grudgingly accepted. Remember, it was still under the 12 month warranty. But Sprints position was they didn't manufacture it.
As soon as I got home, I called retentions and got the $50 credited back to my acct.
The second time it happened to my Instinct, Sprint said it was a known issue, and exchanged it for me on the spot. Two months later I bought the Hero.
Added: I am NOT endorsing buying insurance, just commenting on the ease (or lack thereof) of exchange under warranty.