However, a prosecution on the basis of "impossible" weather would be tricky to say the least. Somebody crazy enough can always do a flight. They would need records from the airports in question.
If it's a rented plane then the aircraft log books can be checked.
If the pilot owns the aircraft they can falsify the aircraft logs as well - and wind the Hobbs meter forwards.
To avoid, as you suggest, airfield records being checked, they could buy their own strip and falsify those records as well (or simply not keep any). And then bribe the neigbours to agree that vastly more flying than was actually the case had happened.
Sounds like a lot of trouble.
(We're talking hours building in a western county here, not someone claiming to have hundreds of hours P1 bush flying in bits of Africa which are harder to check up on.)