As someone who has to sit in the ash at 36,000 feet daily my partner and children are perhaps thankful for the so called prudence and wisdom of those who have more data at their finger tips than most of us on here. If there has been an over reaction ask yourself why ? The litigious society we live in ! Imagine a flame out nowadays, everyone survives but they all sue the airline for post traumatic stress, they sue NATS in fact the passengers sue everyone they can as they now have video footage in the cabin of their trauma ?
So we all sit on the ground for 4 days, nothing happens, no one falls out of the sky that is a successful outcome surely? When you wait for a thunderstorm to pass the end of an airport does it need a jet to fall out of the sky due to a windshear encounter to justify your decision ? Nope its a duty of care that all professionals exercise when they have more data in front of them.
Do we need a jet to fall out of the sky to justify a correct decision ?
Final point, Chemist friend described the difference between volcanic dust and sand dust, sand dust is like the rock in your garden the volcanic has a rough jagged serated edge hence the windscreen damage. Discretion today is the greater part of valour.... Fly safe mon amie