Saved toolbars can be used to load in OP command books on multiplayer

A player can use saved toolbars to save json data filled books in single player, and then copy these books into any multiplayer server where they are in creative mode. These books can run any commands ranging from making someone a server operator, banning someone, giving items, etc.

This does not require a modified game client of any kind, as it only uses the base game saved toolbar feature. This can also be done by anyone regardless of if they are an operator, meaning anyone can drop an operator a book which they may click on, running a command.

This also works on 3rd party server software such as Bukkit, Spigot, etc.

Demonstration video too large to attach shows a book being saved, loaded, and then clicked by an operator: https://youtu.be/e7AzcPuLrdg