I know many will disagree, but absent due process (court), you can’t just take someone’s property.
The teacher has the right to expel the person from the class, but not to take a cell phone. Cell phones cost upwards of $500 and often have very personal and sensitive information on them.
You have a strange interpretation of the 5th Amendment. And you’ve obviously never taught a classroom full of teenagers.
If the school policy states "no cell phones out in class", then the teacher has a perfect right to confiscate the phone. In such cases, the phone is either returned after class, after school, or very typically, it is returned to a parent who has to come to the school to get it.
For real? The phones are confiscated and returned- they are not to be used in the classroom as they disrupt the whole class.
What about a gun?
“.. often have very personal and sensitive information on them”.
Which is why most teens use a password on their phones. Our HS does confiscate them after a verbal warning to put them away. The main office holds them and will give them to a parent or guardian at the end of the school day. During final exams and midterms, if a phone isn’t in a backpack and away from the student, the test is given a 0. TBH, most teachers know the students have them but simply request they not be taken out during instruction and testing.