Laundry systems use this kind of thing, no pin all data stored on the card, many not even encrypted :) I'll assume you aren't using this as a debit card kind of thing where you could phone home for a pin or extended verification.
Looking at the datasheet the only thing unique about the card could be the application identifier, and maybe the extended identification bytes that the factory pre-programs before shipping you the cards.
Due to security purposes every chip is irreversibly coded by a scheme. By this way fraud and
misuse is excluded. The relevant data are programmed in the memory area from address 0 to 31.
Afterwards the associated protection bits are programmed. As an example, figures 12 and 13 show
ATR and Directory Data of Structure 1. When delivered, ATR header, ICM and ICT are
programmed. Siemens programs also the AID. The AID (Application IDentifier) consists of 5 byte
RID (Registered application provider IDentifier) administered by a national registration authority and
of up to 11 byte PIX (Proprietary application Identifier eXtension). There are two possibilities: the
customers AID or Siemens AID (only for sample quantities). Depending on the agreement between
the customer and Siemens ICCF can be also programmed before delivery.
Perhaps you could use that ID along with an encryption scheme incorporating it to at least make it difficult to just read and write the data to a new card. Or even lazier you could assume that no one can buy blank cards with your ID on them to copy too.
Looking at it further though these seem pretty easy to emulate, I'm sure I could make a micro-controller that would behave exactly like this "smart" card and adjust those factory programmable values at will.