Perhaps I wasn't too far off the mark then..
There is a legal requirement that companies assess potential risks to their business and demonstrate that they have take steps to mitigate it. Auditors will not sign off a companies accounts if there is not contingency plan in place - its to protect shareholders.
How much credibility is there in the claim that the possibility of an Icelandic volcano shutting down EU airspace was an unforeseen event?
None. It wasn't just a possibility, it was an absolute certainty to happen eventually.