The 1.7.6 pre-release 1 update for Minecraft means there’s nowhere to hide as Mojang starts to implement unique player IDs.
In Minecraft 1.7.6 a unique ID will be attached to each player which has implications for anyone who should be banned. When 1.8 is released a simple name change is not going to work, so no matter what name someone is playing under they will be identifiable, even if a name is changed.
Player names will be unique thanks to the ID and a name will only become free to use once it’s relinquished by another player. Nathan “Dinnerbone” Adams also posted a quick FAQ which covers most common questions although how name changes will be handled in the future is still unknown.
There are also other changes which include improvements, crash fixes, optimizations and general bug fixes
If I ban a player “Foo” and he changes name to “Bar”, will he stay banned?
Yes. Same for whitelisted players and oped players. They also keep their inventory, pets, statistics and everything they own on a server.
Can I steal somebody’s name? Can I call myself “Dinnerbone” too?
No. I am Dinnerbone and names are still unique. You cannot have the same name as another player, they will have to change their name for you to be able to take it.
How will this work with mods? What about my custom stuff on this one modded server?
Ask your mod maker/server owner. They should be able to support this system easily, but we aren’t responsible for mods or servers!
Can I already change my name? Where do I go? Will it cost? How often can I do it?
We will enable name changing when we feel that enough users are using 1.8 or higher, so that servers have time to switch to the new player formats. We do not have any details on how name changes will be performed or any restrictions that will be required to actually perform a name change. We want it to be easy and freely available, but we also don’t want people changing their name every 5 minutes!
So where do I change my name?
Read the previous answer!
I’m a server owner, what do I have to do when I update to 1.7.6?
Nothing, really. The server will update itself, but it’s entirely possible that it may require your input if it finds an issue (nonexistant players, for example). If your server fails to start then check the log, otherwise it’s ready to play!
Is this compatible with 1.7.5?
No, sorry. We had to change the protocol to support the new player formats.
I’m scared. I need a hug.
Aww, here you go little guy. *hug* Don’t worry, it’s not as scary as it sounds.