Check airmen know no more about flying than line pilots, they chose to be check airmen. I told the story of how my check airman acting as my FO screwed up the automation so much out of SJO I just hand flew our departure and went opposite what he had programmed to follow our clearance. He finally caught up but I wish I had a first year FO that flight to make the automation match our clearance. It is hard to tell your check airman checking you out he doesn't have a clue what he is doing.