I saw a teacher doing that on an episode. Luckily it wasn't in real life but is that even right?
The teacher kept yelling at the student for cheating, disrupting the other students that were trying to take the test, broke his cell and threw him off the his chair. That to me sounds like abuse of power.
If I were the teacher, I wouldn't even announce the cheater in front of class. I would let him finish the exam but still give him the F he deserves. Then I would pull him aside and talk to him in private, asked him for an explanation. There is no need to yell and disrupt the whole class.
The episode to the teacher's reaction is on 5:23 min of the video:
Superb Opinion