You're right. Each store has their own. Gamer's will definitely not be happy when you show up w/ an Animate card LOL!
A general scenario around an (unspecified store's) cashier asking a customer if they have a card, would they like a card, etc. Maybe how to gracisouly decline the offer of starting a card, if that seems like a reasonable conclusion to the conversation.
I guess the point is that often times in convesational classes, the lessons are expressed in a "A says this, B replies with that" progression. Almost anything that can cause a deviation from that path is trouble for a person with limited vocabulary, or limited experience under such stressful conditions. It's been my experience that shopping is a big part of most vacations, so lessons centered around those types of topics pique my interest.
Thanks for lending an ear!