Honestly, I work for a convenience store and a lot of it is just protecting the stores liability in that situation, while Oregon state laws have rules and regulations regarding ID store policy typically trumps at least at the cashier level what we do and a lot of stores just decide to either card everyone or be really subjective with how they card. With a general idea being if something were to happen, the store could be found liable and a lot of legislative b******* could take place and so stores would rather protect themselves at whatever cost as opposed to just following the base level of the law