That beggars the question that if a serious accident occurred TODAY in one of the countries who have not signed up to the 2014 extended deadline and technically have a dual licence requirement in force now how does the insurance stand TODAY?
Pace
I suspect your understanding of how the insurance market works is different from mine.
1. If you infringe the law, and without any specific agreement to the contrary it is up to the insurance company and the courts to decide whether or not you were insured. For example if you have an accident on the road and the car hasnt got an MOT the insurance company potentially have an "out". If the accident had nothing to do with the car's mechanical state some will pay, some will attempt not to. The courts have taken their own view when it has got that far.
2. If you have an agreement with the insurance company they will (or should) honour that agreement. For example when I had just an IMCr and there was the tiresome debate about approach minima I had in writing from my insurance company (and the CAA for that matter) what their position was in the event of an accident.
If I were going to any of the countries in question and was NOT dual licensed I would want to have had the discussion with my insurers at the very least.
However in a case like this an equal risk is having the aircraft grounded (awaiting a qualified pilot) or the pilot "held" for flying the aircraft without a valid license following a ramp check - should it actually ever happen potentially very embarrassing (if a commercial op.) and more than a nuisance.
If you can afford the embarrassment and the cost carry on, if you cant I suspect either hope you stay lucky or get something in writing from each of the relevant countries and the insurance company.