I recently read about a case, Hayes and Hayes v. USA, in which an FAA inspector carried out a flight check sitting on the jump seat. As the inspector had not enough recent experience on the particular aircraft, a Learjet, a safety pilot had been employed. The pilot under test failed to control the aircraft after a simulated engine cut at v1 and the safety pilot had to intervene. Although this constituted a failure of the check the FAA inspector, contrary to FAA procedures, permitted the candidate to repeat the manoeuvre. Needless to say, this resulted in a crash. The safety pilot then sued the US on the basis that the inspector was negligent in giving the candidate pilot a second chance and in providing flight instruction. The lower court apportioned fault between the inspector and the safety pilot which was affirmed by the Appeals Court.
This might not be the case you had in mind, but I think it shows that holding a person in the back responsible doesn't sound so crazy at all.