Actually I've had a problem recently in that I wanted to get some good Converse knockoffs and Amazon was facing limited supply because of attempts on the part of Converse to crack down on this helpful customer-friendly business practice.
[Birkenstock] added that it will also ban any sales of its products by third-party sellers on Amazon
How can they even do that? Amazon isn't their site, and they aren't even going to be an Amazon seller any more. I suppose what they mean is that they won't sell to resellers who sell on Amazon, perhaps? Good luck with that whackamole game.
I guess we'll all turn to Birkenstock knockoffs! :D