Surely fuel is a requirement of all cruises?

Fred Olsen have in the last week announced that they are increasing their fuel surcharge for future cruises.
But surely those nice people at Fred Olsen were aware when pricing their cruises for 2011 and 2012 that fuel would be a large part of their costs.

I am not hugely into politics and I didn't study economics at school but I do know that fuel seems to increase in cost every month and I anticipate that by this time next year I will be paying at least another 20p per litre for my diesel. I allowed for this when considering which car to buy last year and looked at my fuel consumption costs. Fred Olsen though don't seem to be able to anticipate this aswell as me.

I think it is grossly unfair of Fred Olsen to add a surcharge, just because the cost of oil has increased. The price of wheat is particularly high at the moment, perhaps they will impose a surcharge for food soon too.