Several years ago, Bank One tried charging certain customers $3 to transact business with a human teller (instead of using the ATM which was free). It was widely held up by many in the business community (not just in the banking industry) as an example of a company in serious need of a reality check.

Despite that, I'd love to see an airline try it.

Competitors would say "That other airline hates you so much they are going to charge you extra to check in with one of their low-wage counter employees. Here at We Don't Have Our Heap Up Our *** Airline, we'll never charge you extra for checking in. It's just not right."