Yes i have.
I didnt have to show ID, but the girl working there was kinda dumb, she stood infront of me reading the coupon for 10 minutes (like it was a fake or something).

then me and my sister ordered, and we order different drinks. It shouldnt matter cuz they could charge you the more expensive one and give you the cheaper one for free (that would actually save them money and give them a higher profit). But the girl was like, "you have to get the same thing" and i wasnt really in the mood to argue with her, usually i would, but i had the longest day, so i left it. But if i go back, i'll for sure give her a piece of my mind.