I got carded at a gas station when buying beer (I'm in my 60's) recently,
I asked the lady, "Seriously?" she replied that it was store policy.
I told her to keep the beer and went somewhere else. (I was afraid she would see my address and follow me home)
Something like this where the employee is obviously just fulfilling a stupid requirement of their job I would show my ID.
I think the last time I got carded I was buying an R rated movie (The Expendables) at Walmart. I pulled out my license, she didn't even bother to examine it but it fulfilled the requirements of her job