> Right, it seems that they want a KYC list for everyone who bought his art, which isn't possible given the medium.
If that's true, then the medium does not appear to be a lawful method for transactions above €10,000 in the EU.
> Some announcement of that policy would be better than letting it become known through surprise enforcement.
AML 5 - the Directive which introduced this regulation - is not exactly a secret. Especially if transacting through a company, it is very difficult to argue ignorance as a defence to non-compliance.
Traditionally, dealers and auction houses would require and assist with KYC/AML compliance, which was part of the value they offered. Relying on non-compliant permissionless contracts does not absolve the vendor of their responsibilities.