Well I live in Washington. Under the refined code of Washington, rule 28a.600.025
The First Amendment to the United States Constitution, and Article I, sections 5 and 11 of the Washington state Constitution guarantee that students retain their rights of free speech and free exercise of religion, notwithstanding the student's enrollment and attendance in a common school. These rights include, but are not limited to, the right of an individual student to freely express and incorporate the student's religious beliefs and opinions where relevant or appropriate in any and all class work, homework, evaluations or tests.
School personnel may not subject an individual student who expresses religious beliefs or opinions in accordance with this section to any form of retribution or negative consequence and may not penalize the student's standing, evaluations, or privileges
So it's not a problem at my school. Why? Because if they do anything it breaks the students rights.