I suggest that if, during a checkout, the instructor touches any control, that he/she has done so as understood by both of you in a briefing prior to the flight. If you are flying the plane, you should be flying as though you are carrying a non pilot passenger - why would you let them touch anything? As long as there is no life threatening error, the instructor should not touch a thing.
Yes, I've had a few check rides with instructors who obviously did not know the plane as well as I did. Indeed, there had been a few times I have been asked by the check pilot how I did something I'd just done! I've had check pilots who did not know the systems which were less common, and whose handling techniques did not demonstrate care for the plane.
I advise that any "co" flight, where you are flying in the company of another pilot who might think they want to fly at some point along the way requires a preflight briefing. If the pilot not flying wants to help/tweak/adjust, they should ask you permission first. If they want to take control they have control, and you may as well go home then, the checkout is over.
Many times I've had to flight test a plane, and a "company pilot" has accompanied me. After a few imperfect events, I learned the vital need for understanding who would do what, and what could trigger a change in that. My preflight briefing would include: "I will continue to fly the plane no matter what, so you will not need to ever take control. If you wish to take control, say so, and I will transfer control to you fully. But, if you take control, the reason for the test flight has failed, and we're going home.". Which the check pilot should interpret to mean that I would not sign the flight out as having been accomplished, and it would have to be redone. Once, a company pilot complained about how I was flying the plane for the flight test. The boss politely sent him home, I was added to the insurance, and finished the flying myself. Since I have given good briefings, I have never had a cockpit conflict of misunderstanding.
If you're renting, you're proposing to be PIC, so, practice early! You'd tell a passenger not to touch things, so tell the instructor! Doing it preflight sets a professional tone for the flight.