Just in case you thought credit reporting agencies were Your Friend:
In a dozen states, legislatures have set up procedures for residents afraid of identity theft to lock and unlock their credit reports.
But credit-reporting agencies are pushing Congress to override the state laws, which could make it harder for Americans to keep their credit information under wraps.
The agencies [dislike] laws like New Jersey's because they fear that making it too easy to lock a credit report may ruin their business in the way that the Do Not Call list decimated the phone solicitation business. The companies' main business is selling credit information to potential lenders, insurers and even employers. (NY Times)
It seems that you don't own your credit history: the agencies do. And if the agencies' making it available to anyone that requests it allows someone to steal your identity, tough.