Yes. The post below I put in the OCC thread details some of the legal distinctions within the Normandy Peripheral Code.
https://forum.atlas-games.com/t/1221-ooc/6311/174
This post below refers to the conversation that took place in the First Council. All the vis sources are registered with House Mercere, as I recall only the Fair was registered as a seisin.
https://forum.atlas-games.com/t/1220-0-the-first-council/6134/1
And then Alexei kinda made the whole thing a big huge honking deal here: https://forum.atlas-games.com/t/catnip-garlic/129/1
The discussion was about registering vis sources with the Tribunal, not House Mercere, and there is a distinction, one that I thought was understood by the conversation that followed in the First Council thread. House Mercere are like the Swiss banks, they'll keep your secrets and aren't beholden to any particular Tribunal. Continuation of any OCC discussion along these lines should take place in the OCC thread.