So last night I was at a friends house when I got a good idea for a new gamer tag, I decided to check to see if it was available on his Xbox by choosing to change gamer tag and entering a new one but NOT actually changing it. It was available so I was happy about it. When I got home and proceeded to change it all of the sudden it is not available, I try a few more that I tried at his house that were available and all of them are no longer available. I call him and ask him to check and even though it is not available to me, he can change it to it with no problem. So I test out just entering some random name on my Xbox and try the same name out on another Xbox in my house and the name is not available. So why exactly does a gamer tag lock into an account even though the person did not even change it?