I just went to the supermarket, tried to buy some beer, and got carded for the first time since I arrived in Japan!
When buying booze at combinis (convenience stores) they never ask to see ID; instead, they ask you to press a button on a touch screen which says something to the effect of “I declare that I am over 20 years of age.” Only in Japan would an honor system be an effective means of preventing teenagers from buying alcohol.
Anyway, at my local supermarket, it seems that they don’t yet have touch screen technology, so the very nice elderly lady who was serving me asked to see my gaijin card. When she’d checked it out, she gave me a full-on apology for having asked in the first place: something along the lines of “there is no excuse for my behaviour and I am ashamed”. This isn’t quite as melodramatic as it sounds — it’s just an example of the uber-polite language retail workers have to use when speaking to customers in Japan. I can’t imagine getting that response at a Dan Murphy’s!