Maybe it's because I've started to lose interest and faith in Spot, but I've usually been very lenient (probably too much) about checking ID for age-restricted items. If they look old enough, I'll just ask for the guest's date of birth and manually enter it in. In addition, I've never even tried to scan ID at my store to see if it would go through or not. I don't have to worry about alcohol just like Sally, and I've tried my best not to anger guests who already had to wait in line before finally checking out at self-checkout.
Definitely agree with Sally in that I get the feeling my store is pretty lax about checking ID, although I should check with a front end team lead about what my store's leadership wants us to do with regards to checking ID.