Techniques for processing loyalty-based promotions using conventional, retail POS systems with minimal or no required changes to the POS system are described. An identifier is read by a POS system that is conventionally used to read financial cards. The identifier is determined to be a limited identification (“limited ID”) associated with a loyalty program. The limited ID is then stored in a transaction log (“tlog”) at the POS. The limited ID is not communicated to that part of a financial processing network involved in balance access or manipulation, and may in some embodiments not involve the financial processing network at all. The tlog can be analyzed for loyalty program transactions.