Buy it.
The military uses the SS # as its serial #. That's on every piece of mail to and from any GI.
In Texas, the SS # is the driver's license #.
Due to War On Terror "protection", there's a form for the SS # to buy a car from a dealer.
To sell land, the SS# is required on a separate form (I just found this out, yesterday.) if you go through a title company.
In other words, government at the state and federal levels is aiding and abetting identity theft.
In 2004, some 60,000 cases of Identity Theft were investigated.
Aside from having a bank account emptied, or property bought and sold in your name, your credit rating can be thoroughly wrecked and it takes a bunch of time and lawyer money to try to fix things and have a life. Some report two and three years of misery.
And some get caught up in the criminal justice system, if the ID thief uses the name for illegal stuff.
$20/year? Check and see what it covers, but it looks very worthwhile, for starters...
Art