Undo is right .
Regardless of volcanoes, weather (or almost anything else that is not the fault of an airline) the fact is the airline must feed and accommodate you until it provides an alternative flight. Or give a refund.
This ridiculous law means that even when an airport is snowed in for days on end the airline, to whom the passenger may have only given ten euros for the flight, must spend a fortune feeding and accommodating the passenger.
That same passenger will of course expect the airline to always offer really cheap deals, and will wonder why airlines go bust.
Compensation however is a differernt matter. No compensation is given for problems arising out of force majeure delays, though doubtless some EU consumer rights champion will soon insist that the airline hands out a bag of money to each passenger stranded thru no fault of the airline.
For more details see aviationreg.ie -commission for Aviation Regulation,