Comment Bars (Score 1) 144
Or even before the "requesting ID". Let's say you're in a bar (legal: 21 in the USA, legal 18-19 in Canada). By law, persons under the age of majority should never be given entry to the premises. Yet somebody who goes home with somebody from said bar and finds they're under-age by a year or even a few months may find himself/herself facing a serious charge and/or criminal record.
Now if intent and situation were taken into place, then one should consider that one has a reasonable expectation that those you encounter at a law-abiding facility would be of age (and/or that the facility would have some liability for persons that weren't). However, I believe that this argument has been raised before and failed.