The only thing I can think of that you are referring to is the idea of limiting your mint to certain people (e.g. a small community) without falling back into accounts so you never know 100% who spent what and when.
The idea would be to provide a KYC gated way to MINT ecash by paying a Lightning invoice, but spending is unlimited.
So imagine in a community of just you and I, if you wanted to give your friend Bob ecash, you could, and Bob could spend it too, but if Bob wanted to mint ecash to give to you, he can't. Bob is a second class citizen relative to my mint.
The mint never knows who is spending ecash, but the mint can lock away the ability to mint ecash behind a gateway that only certain people can access.
Bob has to pay you the sats directly or pay a lightning address that prompts the Mint to give you the ecash. Bob won't get those ecash tokens himself.
KYC in this context is not official business KYC, it can just be "oh I know that npub, and I trust it. I'll let them be part of my mint". If a business wants to apply real KYC, they can build that themselves.
Also, this would be about identifying customers, not mints. It is not up to mints to reveal themselves to customers, it is up to customers to demand that they reveal themselves or refuse to use their services out of principle.
Using a free mint because they are "cheaper" than the other ones that identify themselves is a risk YOU take to get a better deal over safety.