Under the stress of possibly losing his employment; I don't think so.
Not really. If the tests are reported to the respective CAA and a large quantity of X Airlines pilots are deemed unfit due to fatigue, it could be an evidence to a poor rostering practise on behalf of the airline; they can't kick +50% of their pilots. I think AnthonyGA makes a very good point, hit the airline where it hurts: the pockets. There has to be a way to prove impairment and unfitness due to fatigue.