In my class in medical school, there was this religious Jewish guy named David who always wore a yarmulke (skullcap). During the first two years of medical school, I never saw him without it.
Then sometime in the middle of third year, I ran into David and I noticed he wasn't wearing it. Someone later told me that he stopped wearing it during the clinical rotations.
It always sort of bothered me that David stopped wearing his yarmulke. I don't know if he felt like people were treating him differently because of it or he was being discriminated against. I know that David was going for a very competitive specialty, so his evaluations were really important to him.
On the other hand, there was a Muslim girl in my class who wore a scarf around her head and she kept right on wearing that during her clinical rotations.