I don’t think many ppl holders will ever turn down the opportunity to be paid to fly, I have even heard of PPls approaching owners in neatly ironed shirts with epaulettes, offering to do it for cheaper then the CPLs that they employ, sadly its rampant.
The authorities don’t seem to care, and some owners don’t seem to care either, why would the pilot bother to care what license he holds if he is getting paid?
It all seems ok to the new owner, until something goes wrong or the weather turns bad, and there are plenty of cases were PPls playing CPL fly into the side of a mountain!
http://www.aaiu.ie/upload/general/8253-0.pdf Unfortunately it seems the only people who can stop it are the CPL pilots themselves, by adopting the Taxi driver approach, sad but true!