It seems a few people have figured out how to steal gamertags. It is not yet known if they're using "social networking" to gain access to the account, brute forcing or have some easier method of gamertag hijacking.
"Recently, there have been reports of fraudulent activity and account theft taking place on the Xbox Live network," a Microsoft representative said in a statement provided to CNET News.com. "Security is a top priority for Xbox Live, and we are actively investigating all reports of fraudulent behavior and theft."A few gamers on xbox.com have reported thefts and put in claims to Microsoft's help desk.
One user posted on the forums saying:
"My Xbox Live account was hacked and all credit card info was stolen and used to run up points...Microsoft says: 'Oh, well, better call your credit card companies, nothing we can do,'"Um... "Oh, well, better call your credit card companies" doesn't seem like a typical response you'd receive form a Microsoft Rep. We're thinking some "artistic license" was taken on that phrase.
However, credit card theft is definitely something you report to your credit card company. Microsoft can refund the points, however, it is usually up to the credit card company to decide the fate.
Many reports have come in saying people's accounts were locked or banned due to the theft and Microsoft has been very unwilling to help out. Not a good sign.
If you tick someone off on XBox Live and they threaten to "take your gamertag" - consider yourself warned, they may be telling the truth.
Today, Microsoft is denying the claims of theft. A Microsoft spokesman told the BBC News website that "rumors about accounts being hijacked are false".
source: gamespot