One other thing, sometimes forgotten, is the right of the "student" to call NO if he feels that the safety of the operation is in any way compromised.
Good point of course but has its limitations. For example in the Duchess accident at Camden, the ATO had briefed before the flight that he would be giving the instrument rating renewal candidate a simulated engine failure after take off at Camden. The flight was after dark. The candidate objected on the basis that night engine failures apart from cruise flight was not permitted. The ATO then agreed not to fail the engine on take off.
Shortly after lift-off at Camden and just as the candidate had selected the gear lever up, the ATO placed a map between the mixture levers and the throttles and cut the right engine mixture. The candidate was caught unawares since the briefing indicated it was not going to happen. Thereafter things happened quickly and power was not re-introduced despite the candidate asking for the mixture to be put back to rich and power made available. None of this came out in the ATSB report but came from the candidate after he had recovered from his burns and returned to Canada where he lived.