Knots makes bitcoin permissioned by setting a hard limit at 80 bytes and filtering out transactions which exceed that. Even if block sizes are bellow consensus and fees are paid. Luke and Mechanic think this protects the protocol from arbritary data clogging up blocks. Luke has stated many times that he believes certain transactions are "sinful" and his filters are motivated by such thoughts. FWIW, Bitvmv2 is putting data into the UTXO set not the OP Return like Casey's ordinals. Having a filter enforced limit of 80 bytes on the OP Return that filters those transactions is meaningless.