In doing so, the committee can lift a huge burden from the principal. There is a precedent for bringing members of a community together to help with high-stakes decisions: a jury.
Members of a parent committee can be appointed by the school board or by an elected official. They can be chosen for their level-headedness, high regard in the community, even for their political connections -- it really doesn't matter.
The important qualification for each member is to be a parent of a student at the school. The committee can convene whenever a case meets some predetermined criteria. That may happen a few times a year, or it may never happen, but parents will get a great deal of comfort knowing they are represented in the process.