Is my school allowed to do this?

[Jacob]

Is my school allowed to do the following two things?

Firstly, we are not allowed to have our phones at school. If a teacher confiscates your phone and gives it to the office, this does not always happen, but sometimes the principal will sometimes call you in and make you type in the password to your phone if it has one so that they can go in and read your texts. I have had several people tell me that the principal sits there and tell them that that is the reason they need their password, so that they can read their texts.

Secondly, are they allowed to discipline you over things that do not happen on school grounds? One guy told me that a friend of his had asked about anyone knowing where to buy marijuana on twitter, and he responded saying that he knows people. The office called him in, checked his phone, and searched him and his book sack and then said that they were calling his mother to let her know about it, which they did. Are they allowed to take these actions when they do not occur on school property? Also, if someone ever had the balls to go to the ACLU about this type of stuff, could my school get in trouble? Thanks.