I think that Ryanair had a 3 mill euro fine imposed on them by Italy earlier this week although they are now contesting that- part of the article says:-
Enac found that most other airlines had managed to meet their obligations despite the difficult circumstances.
"At a time when all airlines across Europe were cancelling thousands of flights and disrupting millions of passengers, it is extraordinary that Enac could investigate and then impose a three million euro fine only upon Ryanair," said the airline's spokesman Stephen McNamara.
Ryanair had initially insisted it would only refund the cost of passengers' tickets, but later agreed to fully implement European regulations and pay all "reasonable expenses".
Under EU Regulation 261, if a flight is cancelled, those flying with European carriers into or out of the EU have the right to a refund or to be re-routed.
If passengers chose the latter, they have the right to care - such as accommodation and meals - while they wait."
I think they are also arguing that they should only pay for the costs of the missed flight and from that can deduct their admin charges and if people chose another route home they are liable for those costs themselves. I expect this will run on a bit.