This reminded me of being at Kidani and going to the little shop for a $2.49 item. I had my DVC card and my room card/magic band and they asked for my picture ID. For the 25 cent discount. So, I went back to my room and got the ID. I was in a room within a minute of the store so no big deal.
I learned to carry my ID
. So much for cards and magic bands.
I use my discount daily at the screen door at Boardwalk when staying there. Don't know if they ask for my ID or just the DVC card, but I know I've not had to return to the room to claim my quarter.