I dont see how it's any different to seeing thousands of them clogging up chrono24.
If Costco offered a panerai warranty then it would be different, that endorsement would suggest desperation to sell. But they don't so it's just another grey market retailer.
However, if you think lots of grey market stock devalues a brand, panerai was devalued a looooooooooooong time ago my friend.
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