i agree, the story sounds a bit over the top, but.....

according the VX contract of carriage, you are guaranteed a seat if you purchase one, not a SPECIFIC seat. think about it - if you're in main cabin select and have picked a bulkhead seat, you can be displaced if a disabled passenger or one traveling with a service animal needs that seat. also, you could be displaced due to a federal air marshal needing to be placed on the flight. however, there is usually compensation involved.

neither one of these situations involves the story above, but still....