If a lender of books wants a photo ID to check out books, then that lender should issue photo ID's.   If the lender has chosen to issue faceless "library cards", then, yes, I would resent being asked for additional ID - including photo ID.  

There are several reasons to be wary of additional ID requests:

1.                  Such requests are open to discriminatory application.

2.                  When you bring only your library card to the library – which is all the library required when they issued the card – to be told, or asked, for additional ID (maybe you left your wallet at home) means you might be denied service. 

3.                  Where does the additional ID request end up – does it include a request for your Social Security Number?  That would clearly be out of bounds.

  Here's the deal Jeff--You are required to show a photo ID to sign-up for a library card.  From CPL's web page:

How to Apply for a Library Card:

• You must apply in person at the Main Library Lending Department or the Public Administration Library downtown, or at any other of the Library's 28 branches.
• Adult applicants must present photo identification, such as a valid driver's license or State ID, and proof of their current address, if not listed on the photo ID. For teenagers 14-17, identification is required; a current report card or a class schedule are acceptable for applicants who do not have a photo ID.  Children 13 and under are expected to print their name, and provide their address and birth date.  The signature of a parent or guardian is required for children six and under.
• Homebound persons in Cuyahoga County who wish to obtain a library card and to use the Library's services should review the information regarding the Cleveland Public Library's Homebound Services.

I forgot the legal/latin term, but there is a principle based on precedent that an initial standard imposed implies possible later application of that standard. ( "a priori"???)

I am tired of a society that operates without common sense.  Ask these kids how many identities they are going by these days?  They learn the tricks young--unfortunately from their parents. 

 Merchants and credit cards don't care about protecting your identity until it interferes with the cost of doing business.  Credit cards eat some of the cost of fraud payouts, because they don't want folks to stop using their credit cards.  Ditto--libraries.

Hospitals routinely now ask patients for photo ID with their insurance card, because the cost of not doing it for hospitals has become too high. 

Many institutions, including libraries, should put patron ID protection and on line security first--not the cost of doing business, especially when taxpayers eat that cost.

Libraries need to state their borrowing standards and prosecute offenders of that standard.  One card, one user is an obvious standard and fines over a certain level warrant recourse:

 From CCPL's website:

Only one card per individual borrower.

And

Collection Agency

Anyone who has items more than 60 days overdue and a balance of $100 in fines/fees may be referred to a Collection Agency.

A $10.00 collection agency service fee will be added to the fine record. Borrowing privileges will be removed once an account has been turned over to Collections. Payment arrangement can be established.

Once the materials have been returned and all fines/fees have ben paid in full, all borrowing privileges will be reinstated.

Thank you Sheryl Harris!!   Please read and pass along this important information.