Did you already wipe the crystal with a damp soft cloth? These kind of stripes happen to me sometimes, maybe a residu of fat fingers or the like: after breathing on the crystal and wiping it with a soft cloth they disappear and the watch looks brand new again. It is the same as with glasses that maybe twice a day have some stripes and spots, and are treated as described. If the stripes don't disappear: hmm, unlucky you, you have to go to the AD with it, I certainly would feel extremely uneasy about it, because the potential blaming game is sometimes a nasty one. Good luck!
Kind regards,
Paul