777fly wrote: "It occurs to me that, in the event of total radio failure, we would be expected to follow our flightplan to destination anyway! Could we then expect a fighter escort if we penetrate one of these international boundaries without passing a clearance number or even talking to the control centre at all?"
In case of com failure you would follow your flightplan and set 7600 on the transponder, wouldn't you?
If you didn't, you would probably be intercepted and forced down somewhere.