Not really - the PAX aren't confused. Some PAX are just thick or ignorant. If they are asked politely & often enough then they'll show the boarding card without questioning why - it isn't high up the list of 'Important Things in My Life I Worry About' and so if someone wants to see the boarding card they'll show it and if they aren't asked then mostly they won't.
Getting confused about showing it is irrelevant - no more confused and going to use a different bus company and finding out say they have a fancy prepaid card to use as a ticket.
The confusion level would be 'Oh well fancy that'.