would it be possible for the script to be client sided? to just not show the script's effects for the people who install it?
That would essentially allow for you to change the way other players look from your own client, which is entirely impossible without code injection or something similar.
Just read this.
I might tell you there is a possibility to hack the packets sent to server.
The server will then think you are host.
You can then open mission editor.
That might be how he REALLY did it.
I know what I talk about.
You CAN hack Blockland.
I doubt you would be able to do this on a listen server or a dedicated server.
The server would check everything you do. If you don't show up as an admin, you wouldn't be able to do anything. If you don't send the correct admin password, you wouldn't be able to become an admin.