My mother is a teacher, and her school has gone through many different lawsuits from parents. In theory the staff are protected from liability, but if you think that going through a legal case is not stressful for the school from the principal to the teachers and counselors I don't know what to tell you. It only takes one parent out the hundreds to thousands of students at a school to make a mark. They can and often will go after the school for any little thing, from dress code to phones, to teachers being too easy to teachers being too hard. Anything that they perceive as giving a disadvantage to their children or that they don't like they will go after if they think they have a chance.