T
You make excellent points.
Unlike in your position, dangling the carrot of "800 other people vying for your spot" would not likely work. I suppose it comes down to finding out what a person's "currency" is.
Also, college students are legally, if not frontal-lobally (I make up my own terminology

) adults. In this case, the student is a child who recently lost her mother and is in foster care.
I agree that a child who is consistently unable or unwilling to respect the classroom environment should have that privilege suspended. At this point, I have not seen or read that this girl was a habitual offender. And even were this the case, the obscene show of violence recorded on video is totally unjustified.
Honestly, I don't know what the perfect solution would have been. I can say with confidence, though, this was not it.
In my mind I have been playing over a variation of something I do with my children, who are much younger.
I make a verbal request. I wait for a response. If none, I make my request again. If no response, I suggest that the child can do as asked or perhaps they are in need of my help. Which is Kryptonite to young children. "NOOOOO! I can do it!".
If that does not work, they are removed from that specific activity/lesson.
Now I know this is not feasible with a teen. But some of the basics might apply.
Should she ignore my request to hand over the phone (and nowhere have I read she was yakking loudly during class, but that she was not paying attention in class) I would maybe say, "When you break the rules, you will not be permitted back into our class. If you are not permitted back into our class, you will not be able to do the work required to pass. Would you like to make a smart choice or a foolish one?" If she refuses still, then I might go about
teaching the rest of my period. Afterwards, inform the office that
this student violated classroom policy and is
to be suspended for x days.
It is a lot easier(and less violent) to deny admittance to rather than remove an unwilling person. And also, I think this method would place the onus on the child. After all, she was allowed to make that choice. Hopefully, this would serve as a learning experience.
Again, this is if the child is breaking a rule that is not distracting or harming other kids.(which would warrant serious intervention to protect other children) Teens may be toddlers redux, but they are capable of feeling regret. By offering the child the opportunity to make a good choice rather than "coming at them" , it places the consequences squarely in their laps.
Sorry for yet another long-winded blah blah blah. I am thinking things out as I type.