I agree with “cantoresq”.
No rebbe or menahel should consider this type of step without thinking hard about if they’d consider this a fair way of dealing with their own child.
No yeshiva or bais yakov should consider taking such a drastic step unless they have exhaustively considered any, every, and all possible alternatives.
If parents have to be asked to remove their child from a school it should be done in the most bekovadik, private way possible, and the school should also continue to be involved in helping the parents place the child elsewhere.