A & C, I agree with your comments about low hour pilots and supervision with respect to entries in the Tech Log.
However, this is not the situation I am alluding to. I am specifically concerned with non licensed personnel carrying out maintainence/defect rectification and the ramifications that this has with respect to legality, insurance and liability etc.
Several years ago my father (RIP) who was a veteran light aircraft instructor appeared as an expert witness when an instructor brought a case against the club/school for illegal/unauthorised maintenance after he was badly injured following a real EFATO. He won his case and a lot of money!
People who carry out these acts of illegal maintenance must realise that one day they might have blood on their hands and should leave the job of maintenance to a properly licensed engineer.
Finally, I have been around the tracks long enough to know that this sort of thing goes on but that does not mean to say the situation is acceptable.