Pardon me, but the used - resale scenario is precisely why Schoeps should be reluctant to certify a pair of capsules that they haven't measured in years. Who knows what those capsules have been through in the meantime?
ero3030, you have it exactly right, but a lot of other people don't, and that's why the concern exists. People say that they don't believe in magic words, but then they turn around and act as if they do. About half the ads on eBay for arbitrary pairs of microphones--including heavily-used microphones described as "vintage"--claim that the microphones are "matched pairs". It's unfortunately up to the seller to decide what that phrase should mean, and up to the buyer to find out what the seller means by it. I suspect that it often means, "I hope I can find a buyer who is easily conned."
When responsible manufacturers use the term, it relates to their initial delivery of a pair (or larger set) of new capsules or microphones from the factory. This is true at least for Neumann, Schoeps, and Microtech Gefell that I know of. It's a serious descriptive statement, but not a guarantee of future magical protection, and it's not transferable to any other, subsequent resellers after the equipment has been used.