If the cost difference is so huge as to attract people to as you put it grey operations then you have to ask why?
When all of the indirect costs of an aircraft are covered by the owner, then its extremely easy to see how operators can charge lower prices for their services. Many cases of someone approaching an owner and saying, "hey i can make you some money with your aircraft"...... owner agrees.
Your view appears to be based on the highly regulated European environment, mine is from a less regulated part of the world.
So the UNSAFE claim is a load of B+ls
Whats the saying, lies, damn lies and statistics! Once again you are looking at this from a regulated environment.
If you dont like the term Gray Market, lets change it to Black Market.....
I dont think that its coincidental that the French authorities question passengers on flights from this part of the world about how they happened to be on the aircraft, and did they pay for it. They are making a concerted effort to stop these flights from operating into Europe.
The grey/black market exists in this part of the world, it might not be in your part
Mutt