Yeah, that's my understanding of what they call "soft consensus" - you put the data on the blockchain so it can be verified by others (instead of having a smart contract on the blockchain that does one verification for everyone). So everyone can verify that a Hive community starts with 1, and therefore what is allowed and what isn't.
But maybe @roadscape can chime in and let us know about the design of Hive communities and the possibility of changing their type or permission levels.
If he has time sure, I know he reads posts in this community.