This would be tricky to do as NFC Ring Control doesn't do a read before it does a write. It's probably doable if we did a read before write and had some sort of guaranteed identifier on NFC Ring Unlock written tags but this would potentially give context to the NFC Ring Unlock tag data which would provide context for an attacker (they would know what the data could be used for).

So while it's doable it wont be on my urgent list until we have strong crypto on a ring.