Held hostage by the airline - literally
 

My GF's family likes to tell this story:

After a family visit to Austria in the early '70s, they were leaving VIE for AMS and YYC early one morning when the KL check in desk decided that the fare they paid was too low (and these were the days of carbon tickets - not even carbonless). Since this was in the days before credit cards, the family didn't exactly have payment for whatever KL @ VIE wanted. It so happened that my GF's grandparents had gone to the airport, not that they had the money either.

What was the solution? The grandmother was locked away in a secure room in VIE while the grandfather went to the bank to get money for the ransom.

Airline kidnap & ransom couldn't get better than this?

Thankfully BA didn't try this on us when we were returning from VIE on the $20 W+ tickets 30 years later. :D