It will only be replaced if it has a factory defect and if it has less than 12k miles. When I say defect, I don't mean the clutch starts slipping. I mean a spring fell off the disk and cause the entire thing to fail or the throwout bearing failed. This is extremely rare, though, and they first have to take everything apart to see if it's a defective part that is covered under warranty or simple wear and tear (or abuse), which would not be covered under warranty.
I blew out my stocker at 7500 miles after lots of drag racing and autocrossing (many 12.2s and 12.3s in the 1/4). when they took it apart, both the pressure plate and flywheel were turned into mirrors from excessive heat, so it was obvious that it would not be covered. I just had to pay to have the ACT installed and go on my merry way.