I have some concerns about the update

make a file named reservednames.txt in the base folder of the server and add all names you want protected and not spoofed in it like

name:uid-number
name:uid-number

and you will be able to protect the admin's names and all regular player's names from being used.
if you want to ban a particular name you can do it this way

name:

and leave the uid blank and that name will no longer be able to be used.

Quote from migdyn

I think I will make a plugin that will reserve every name that join automatically.

that would be very handy. The list of player names and uid numbers is already available through the world db. The .db file can be accessed by DBbrowser and all the info obtained that way but a plugin to access this db would be very handy.