I used to think similarly to Mr Ralls (I'm 26 but still get ID'd plenty of times) but after talking to a cashier about it I found out that, if they serve someone under the legal age, not only does the store get its knuckles rapped but the cashier themselves is fined and likely loses their job.
If it were me manning the till, I'd ask everyone - that way, when some annoyed just-over-the-age shopper says "I'm old enough, dammit" I can say with an honest conscience "yes, but I ask everybody". Admittedly, I would've said it with a bit of a smile to this particular wrinkly old puffin, but who knows what sort of day the cashier had been having - did Mr Hall greet her with a cheery hello or was he as grumpy as this whole story would suggest?
If it were me manning the till, I'd ask everyone - that way, when some annoyed just-over-the-age shopper says "I'm old enough, dammit" I can say with an honest conscience "yes, but I ask everybody". Admittedly, I would've said it with a bit of a smile to this particular wrinkly old puffin, but who knows what sort of day the cashier had been having - did Mr Hall greet her with a cheery hello or was he as grumpy as this whole story would suggest?