Agma suggestion (locked name)

[Sora]

Locked nicknames cannot be implemented since there are multiple issues behind. It is a nice idea. It was partly worked on, but there were too many conflicting issues with the idea. (players who are already spawned with a specific nick, players on other gameservers, duration of nickname lock, user interface for it all, skins previously attached to a locked name, and more)
Remmeber that you have both username, and nickname. Username cannot change and is unique, but nickname can change and is not. It might be possible in the future to right click a playercell and view its username if logged in. As well as viewing player's level. That should make it impossible for someone to fake being you.