Re:The law is actually not so black and white here (Score 1)

Check out the Social Security Administration's pamphlet here. It says that while you can refuse to give your number, some companies are allowed to refuse to provide services to you if you deny it to them.

Yale University had a problem over the summer with a graduate student who took the numbers he had access to and applied for credit cards with them. The cost: some $120,000 in charges. Apparently he's now in jail, but it shows you have to guard the number anyway.