What are the "rarest" BDs?

[BluBonnet]

re: REDS, I guess it is possible that it is technically OOP even if Amazon still has a bunch in stock.

But that just raises the question: does the OOP status mean something different to different folks? I suppose technically when a title is no longer being produced, it may qualify as OOP even if most of the online stores (and maybe even B&M stores) still have enough for a while.

For most people, I think OOP means that they are probably not going to find it anywhere, unless it's an incredibly obscure store or through an eBay reseller or an Amazon 3rd-party reseller.

Criterion has been kind enough to give us a heads-up when one of their titles is going OOP, and as a result, if you're fast enough you may still be able to get one from Amazon before they run out of stock, which may happen within days of the Criterion announcement.