I was reading Evan Schumans’ blog post Sears, OfficeMax Agree To Pay In Gift Card Patent Lawsuit, this evening. It appears that there is a company called Card Activation Technologies that has a patent on a gift card validation process:
The Patent itself (click for full text of Patent 6,032,859) was filed in 1996, and it anticipated the next wave of gift card and phone card usage. At the time, the cards were issued for a specific value and then thrown away when emptied. The Patent envisioned POS units that could add and deduct value. Such POS processes are commonplace today, and therein lies the Patent infringement issue.
I have not read the patent in detail, I probably will - but I found this interesting. The article has stated that other companies have either settled or agreed to a licensed agreement with Card Activation Technologies.