I remember once when I worked on check-in, the computers had gone down so we were using a manual system (pen and paper). That afternoon the system came on-line and I was asked to input all of the manifests into the computer. The quickest way to do this was to check-in ALL of the passengers, and remove the ones that didn't show.
Anyway, after completing this laborious task, I went back to my desk. I Went to check-in the first passenger, loaded up the flight, and typed CALL.
"Are you sure you want to check-in all pax" Y/N"
You guessed it...
I pressed Y
The Boarding Pass Printer spat out 143 boarding cards, and we now had no idea who was checked-in
Only one thing for it. A full baggage ID, which delayed the flight nearly 2 hours