There's not much he can possibly do in a little box.
Then why are you complaining that he shouldn't be in your server?
All I did was disable jets.
Several times in this thread, you've mentioned doing things other than disabling jets.
For one thing, you just said you literally restricted every feature past v1 to everybody but yourself.
I assume that includes more than just jets.
And even if you did disable jets, not having jets in a freebuild generally makes the game less enjoyable to most people.
Not that i think you'd care, since as far as i'm aware literally the only reason your server is public and multiplayer is that you want to show off your castle to people.
The founding fathers didn't have jets when they built this country.
I don't think they had computers either, but you're using one right now.
Also, building a country and playing blockland are two entirely different things.