Card Sticker - new stupid rules, WHY?

Just went to Foodeez in Diep River, where the card sticker promotion, has now changed the rules "no card, no sticker". I argued with the staff there about how stupid the rule is and some clever man kept repeating "rules are rules" with an idiotic smile on his face. And I was forced to put my sticker on a new card, instead being allowed to take the sticker with the paper backing and use it with my old card at home. I just went home and added the sticker to my old card. Who made such a idiotic rule?