It really depends on the judge, and the circumstances of the case that's being adjudicated. Some judges don't allow head covering of any kind in their courtrooms. As such, yarmulkes, Sikh turbans, hijabs and other religious or secular hats/scarves/coverings must be removed.
I've been in Federal Court when defense counsel has asked that the prosecution cover or remove a Crucifix she was wearing outside her blouse. The judge instructed it so. It happens with some frequency.
In NYC court proceedings are routinely recessed for the High Holydays if any of the participants,including jurors, are observant.While this is not a similar situation, it does demonstrate the system’s deference to religious practice.