All customers are smarter than average
In study after study, respondents rate themselves as less racist than average, smarter than average, more generous than average.
And though they are never asked, I'm pretty certain that your customers also believe that they are righter than average as well.
At the airport yesterday, a woman at security said to the TSA official, "I'm a regular traveler, a frequent flyer and I know the rules. I want the fast line." A moment later, it was determined that the woman had two huge bottles of shampoo in her very large carry on. "No one told me that there was a restriction on liquids! Where does it say that?" she snarled, as she stood in front of the sign that said that...
Any time you ask customers to self-segregate, they will put themselves in the best line.
And just about any time you ask a customer to acknowledge that they were wrong, you will fail.