I think the other thing we have to assume here is that the pilot actually does indeed own the engine.
I own several aircraft and as an engineer would be aghast if I discovered some pilot had been experimenting after reading something on the internet.
Pilots have very little technical knowledge, period.
The CPL syllabus is little more than a little useless theory and basic principles of a piston engine. It is pretty obvious from other threads, plus my own experiences, that the rating training takes it little further. More often than not it is a POH quiz.
I have stated here before that a LAME would never look in that handbook for anything engineering related to the aircraft.
The owner, Chief Pilot and Chief Engineer normally agree on an engine operating policy for the company. It may be iaw the POH or they may have something written up in the Operations Manual.
If a pilot has a good idea on how to operate the engines a little different then I am sure the management would love to have the opportunity to discuss it.
We have recently seen a pilot accept a 29" Take-off on an aircraft without any consideration to the induction flow on an engine with an inop turbocharger.
I guess we are talking $80,000 of engine, it is not a plaything for a bored 250 hr pilot.
The Chief Pilot, and others, rightfully assume the aircraft is being operated iaw the procedures and guidelines.
Just a thought.
