Arguing that "a witness's ability to testify cannot be made contingent upon the violation of her religious beliefs", the Baptist Joint Committee and other religious liberty groups filed a statement with the Michigan Supreme Court. The state is considering an amendment to the rules of evidence that would allow judges to require removal of all head coverings regardless of religious significance. 

From the BJC press release:

K. Hollyn Hollman, General Counsel for the Baptist Joint Committee, said that the proposed rule is wrong because it targets a religious minority, an example of a majoritarian viewpoint that unconstitutionally curtails religious freedom rights.

"A court should be leery of making one-size-fits-all rules when it comes to something as important and as diverse as religiously motivated dress or conduct," Hollman said. "There are other ways to assess witnesses' credibility – ways that would respect the constitutional and practical considerations of the justice system without trampling the free exercise rights of a religious minority – that the very capable jurists of Michigan can employ."

You can read the entire statement here (pdf).