Supply and demand or plain old Price-gouging?

My mother was supposed to fly to Dublin last Saturday. Needless to say Iceland's volcanic ash put paid to that and she's now had to re-book the flights. Because her homeward bound flight wasn't technically canceled, instead of shoving the whole booking along by a few days, she had to cancel the original booking and basically book herself new flights. Lo and behold she is now paying about five times more than she originally did, even though it's with the same airline and they canceled the flights. I realise that the airlines were at the mercy of the gods, and were losing millions of dollars per day during the flight ban, but jacking the prices up for existing customers seems a tad erm, well, disgusting to me.

I suppose it's the old supply and demand argument. Or is it? In my opinion this is plain greed, or price gouging, definid by Wiki as "a type of a speculation with a seller (speculator) pricing much higher than is considered reasonable or fair." In some states here it is illegal in times of civil emergencies.

And the airlines weren't the only greedy basterds. Apparently people stranded all over the world suddenly found hotel prices had more than doubled following the erruption. Eusrostar's prices also rocketed as everyone scrambled to reach the Continent by other means and Eurostar hadn't even been losing money hand over fist in the previous few days.

There's one argument that, in times of crisis, if people don't raise the price of everything, shoppers will clean the shelves of the stocks and thereby deprive everyone else of them. Okay, I get that. After hurrican Katrina, vendors not only raised the price of a bag of ice from $2 to $10 but they limited the amount you could buy. That way everyone (who could afford it) had a fair shot.

Unfortunately this doesn't quite fit the airlines' price-gouging. These were existing customers who had already paid for a ticket. Sure. they'll get a refund for the canceled flight, but charging them hundreds more for something that wasn't the customer's fault in the first place just seems to be plain wrong.