If someone is turned away, it shouldn’t be a surprise. Every place I’ve seen that requires AOW for particular sites makes the requirement explicit somewhere in the reservation process.
Nevertheless, I completely understand the frustration of, say, a skilled, experienced diver with 200 dives in all manner of conditions who isn’t allowed to make a dive that a brand new AOW with barely ten dives is cheerfully permitted to undertake without being questioned.
As useless as the AOW cert may seem to these experienced divers, the purchase price may be easier to stomach if you divide the cost by the number of years you hope to dive and consider it your annual fee to do the dives you want without having to justify your experience.
But, yeah, the whole “pay to get a card to help someone else reduce his liability” dynamic is awkward for everyone.