yeah if a person had enough info on that account they can call an UA in "Unauthorized Access"Cole said:Yes. I was speaking with an XBL Agent about another issue. She asked if I had any other questions at the end, and I asked this exact question.
She told me that if someone was to file an "Unauthorized Access" on the gamertag, and if they find that someone gained access to the account, and changed the gamertag, then the person that called it in will get his tag back.