I think the focus should be on reminding the child that certain behavior is unacceptable rather than on understanding the root cause.
I disagree. Rudeness serves a purpose for the person using it. Some unspoken need is being met with the behaviours, and the behaviours will continue or manifest in more hidden, and possibly damaging, ways if the surface expression of the underlying need is suppressed.
If she is meeting a need that is too complex for her to communicate politely or which is beyond her awareness, coaching on appropriate ways to express herself and gentle discussions with a parent will provide a better outlet for the upset. Critiquing and punishing the behaviour without communicating a commitment to help the child will just reduce future communication between the parent and child, erode trust, and reduce the effectiveness of future parental interventions.
