You *don't* have to give your SSN to your dentist, or your doctor, or your driver's license bureau. But it sure is hell trying to get them to accept that. I suppose you could sue them if they refused you service if you didn't give it to them, but geez, think of the costs of a lawyer and what you'd actually gain.

www.overlawyered.com is a favorite site of mine, but in this case maybe we're underlawyered?