It is policy. Even if the engineer thinks he is okay, they are sent home - for safety I imagine. Kevin told me that one of his students crashed her bike into his car (he was parked), and ended up on the windshield. The students were standing around and he said, "For once can you do something useful with your damn iPhones and call 911." An ambulance came and got the student and, even though Kevin wanted to work, the school made him go home for the day. My uncle was in the navy during World War II. His boat got torpedoed. Everyone who survived was given one week's leave. Same stuff, I guess.
I imagine they are right to make it so. It's gotta be something underlying at first with the trauma. I mean you really can't have someone second guessing themselves when operating heavy machinery even if it is a slight difference in the way they do their jobs.