Isn't it also a Client/Server sided effect?
I am not to good at scripting, i may be wrong.
A client.cs can modify the server and a server.cs can modify the client. It's just highly unrecommended.
client.cs executes automatically. There is no toggling these. They execute once Blockland starts up unless you're running a dedicated server.
server.cs only executes if you enable it in the add-on's list. They execute when the server starts. Do not execute when you join other servers.