I think most ticket counter or gate agents would never know who's a Companion Pass holder or who isn't. Probably the only way they'd know is if the CP holder actually showed the agent the card and was traveling with the designatee and they needed a ticket printed up. It's not like other carriers where the customer shows his Gold card hoping to get bumped to First or some other perk. I can't think why a customer would show his/her Companion card.