Username Case Change Exploit

This is more of a server sided bug. I know people who have found an exploit where you can change the case of your username.

Example:
If your username is Sergee237, you can login to a server with sErGeE237 or SERGEE237. This creates a new profile as if this player is new on a Multiplayer server. I cannot state how to replicated the bug, as it is a private 'method' according to the people who found the exploit/bug, but I'm sure if you look through the code for the authentication/login system or something else, you will find how this is being done and put it to an end.

Also, this is a way to bypass bans on a server, making servers very insecure.