Currently if you go to a student's profile page and go Contact > All teachers, it doesn't actually email ALL teachers of that student. If a class has different teachers for the same class but on different days, it only emails the teacher that is teaching the class on the day you send the email. E.g. If Mr. Smith teaches MAT092A on Monday and Tuesday but Mrs. Smith teaches it on Thursday and Friday, if you send the email on a Monday it will only go to Mr. Smith.