I review the guidelines and questions before I go on a shop. I have been shopping since 2006 and I contacted the scheduler many times when the editor wanted me to do or say something that no customer would say or do. The schedulers do not want shoppers to be detected as they would have to send another shopper out with similar results. If the offending instruction or guideline was not revealed BEFORE i accepted the shop I am not obligated to perform as no "meeting of the minds" occurred to create a contract.
I usually am thanked and GET AN E_MAIL amending the instruction. If the scheduler will not send me an e-mail agreeing to the original agreememt or acceptable guidelines I ask that the scheduler find another shopper and remove me from the shop WITHOUT PENALTY as the terms were not revealed prior to my accepting the shop.
If an issue like the one you describe occurs or the editor sends the narrative back asking that I falsify or deviate from the observation I made I contact the scheduler. I will reword the narrative and change my negative to a positive as follows. I will repeat my observations and state I do not have knowledge of the clients employee handbook or requirements but if (this that and the other thing) is acceptable the employee's performance was outstanding and the observations were likewise acceptable. The editor would have to falsify the report. I keep a copy of the papers including the original report and amended report. If am penalized (not paid for the shop) I remove the MSC from my list of clients I will work for. Fool me once shame on you, fool with me twice shame on me.