^+1, stonechips unlikely to be covered as they're not manufacturing defects.
I had 2 of my diamond cut alloys replaced under warranty on my mk6 GTD, as they'd succumbed to the dreaded whiteworm corrosion around the centre of each wheel. Dealer told me that if they'd been curbed or scuffed (they weren't), it was unlikely VW would've agreed to change them, as to do so would be considered to be 'betterment'.