The idea is to ask the other students leave and let their education continue. Let the administrators handle it after that. With no audience. The audience is everything. Remove that, and the offender backs down quickly.
No. You really don't understand what I see on a daily basis...and you don't see what's being reported every day. It's not about audience, it's about authority.
Inner-city high school teacher here. And what you said is only partly true. Yes, sometimes a student is disruptive to get attention. That's not uncommon, particularly in the lower grades.
But there could be other reasons for that student's misbehavior. A student might use a cell phone in class to deliberately challenge the teacher's authority. Or the student might simply want to talk on the phone at that particular moment.
I've seen a lot of that. And in these last two cases, removing the audience would have no effect. In fact, it would be a student "victory".
Musical classrooms for the terminally clueless.