SAS, there we go again, agreeing violently.....
If you read my post I quite clearly state that if they are current and safe and this is an "insurance" check ride then there is nothing for me to do and therefore I am happy for them to be P1 while I watch.
However if they are in need of Instruction then I am commander and it becomes a lesson. You are absolutely right that a lot of pilots require some form of Instruction during something as basic as a check flight. But I also prepared to be flexible and pragmatic enough to give someone who is current and safe the benefit.
I don't know perhaps it's the hundreds of times this has happened (and lack of currency has never been a problem...) to me was the reason I became an Instructor......