Preventive measure: get Scrum Master certified yourself. The training can even be fun with a good instructor.
Then when professional managers come sniffing around muttering about Scrum, you say: "I am a certified Scrum Master. Our process is already 100% Scrum.
Smart defensive move.
That's when it stops being team member helping out and becomes process person from outside.
If there is something positive about agile in low-trust situations it is, without agile, people can kick the can down the road a long way (six months!) before there is a confrontation that reveals the low trust problem. With agile it leads to meeting after nerve-wracking meeting... which of course can wear you out.