Are you saying he was returning from the Mediterranean in his single engined 172 and what do you mean by the perimeter. If there was an air exclusion zone he would have been aware of this when he filed a flight plan as it would have been published in the SNN NOTAMS. He would have to have filed a flight plan for such a flight. He would also have contacted SNN Approach long before he entered their airspace and would have been advised of an air exclusion notice. I fear this is a story of fancy, but it sounds good to people who don't fly!!