330 views | 21 | Last updated on Jun 23, 2015 Consumer Protection
The U.S. Social Security Administration addresses this question on their website. They state:
Anyone can refuse to disclose his or her number, but the requester can refuse its services if you do not give it. Businesses, banks, schools, private agencies, etc., are free to request someone's number and use it for any purpose that does not violate a federal or state law. Sometimes they will issue a different number if you ask.
Also in Title 11 is the Identity Theft Enforcement and Protection Act, chapter 521. You may want to review those laws as they deal with the unauthorized use of identifying information.