All this is ar*se covering by anally retarded officials who refuse to move a finger until they have a legal liability backstop in place.
I don't think anybody has actually seen any of this "ash", anywhere in Europe, at a concentration which could conceivably affect any type of engine or aircraft.
I was in Germany a few days ago and apparently the airlines there are blaming the UK Met Office for spreading a load of bull and causing the recent disruption, and they don't think there is any danger to aircraft.
For my June holiday down to Greece, I will bring VFR charts (of some kind...) because it seems sure one will always be able to get back to the UK, via France, under VFR. Whereas if one takes an airliner, and they ban IFR/CAS, one could get screwed just like countless thousands got screwed recently, with Eurostar screwing people for 600 euros a ticket.