The Los Angeles Times (via Yahoo! News) has a good article on the ubiquity of the social security number for many federal government programs in the United States. While consumers are told to make sure they don't have their SSNs in their wallets in case they are stolen, federal medicare cards use that number as the identifier and are routinely collected when medical and drug services are used. This, some feel, leave the users of this program more vulnerable to identity theft.
More egregious (and nothing short of criminal), according to Beth Givens, executive director of the Privacy Rights Clearinghouse, is that military personnel use the SSN as their primary identifier and are required to stencil it on their luggage.
While the risk is acknowledged, the costs of retooling systems is coupled with bureaucratic intertia to thwart change.
Read the full article here: U.S. Policy on Medicare Cards Is a Boon for Identity Thieves - Yahoo! News.