Reading over this thread reminds me of Kettle experience that I witnessed in Honolulu on Sunday...

The man, who looks like he is from the mid-west, walks up to the TDC and hands over his ID and what he though was his boarding pass. TDC tells him that he gave her his flight detail page, and not a boarding pass, and needs to go back to the counter. He just stood there for a minute or two, staring at her, until he finally took the papers back from her and went over to the ticket counter to get a boarding pass..