And just to clarify why we're doing this...
Once you have access to host a game with scripting capabilities, nearly everything can be customised.
If a user hosts a game, they could easily change it so that the nickname of the user gets changed to something else. So even if RandomUser connects to a game, they could easily change the scripts to change the nickname, change the score list, etc.
So you're asking for your nicknames to be registered, even though we can't guarantee anything with other servers. So to pretend that your nickname is actually secure on other servers would actually be a bad idea, as you might trust that a GReaper on another server is me.
To be absolutely clear - it isn't impossible to secure it, but the amount of effort required to do so would require hardcoding quite a bit of code and moving it out of script. Given that we're a free game with a small community - it just isn't worth it.