We haven't been hit with a separate terrorism clause yet, but the company we sometimes rent aircraft from in Saskatchewan put an lease-back Arrow (Pa28-200R) on the line a few years ago. It had an insurance premium of $3,500 added to their fleet policy. Last year, (7 weeks after 9/11) that was doubled, and we all thought of the terrible cost in insurance we would all be paying for that day. This year, they were quoted $23,500 (all in Canadian dollars @ about 0. 65) for the same airplane!!!!! (the company has a zero claims record). Today, the aircraft is no longer on the line, and this operator (like many others) will reduce his coverage to corporate liability and hull coverage will be provided from the customers with "renter's insurance".
We have had similar experience with motorsport insurance. Many events cannot be covered and those that can are at at least double the price.
The real cause is not JUST the greed and avorice of insurance underwriters, it is the individual greed of people cashing in on the Legal Liability Lottery that pervades the US economy and culture. Do you realize that the ratio of lawyers/capita in the US is 10:1 over Canada and 30:1 over Japan?? Who do you think is paying for all of that absolute waste of skin??
Until the US comes to its senses and dumps almost the entire boatload of legal parasites, you will not solve this problem.
Pat