Sometimes volunteers in classrooms need assistance. Maybe a child needs a parent, or they need help to clean up a spill, or they need more volunteers.
An easy way to get the attention of a hall monitor or Kids Director is to use this sign. I saw this when I went to visit Northpoint Community Church in Atlanta. Each preschool room had one of these signs that they could just wave out the door when they needed someone. As long as someone is assigned to being a hall monitor, this system could work!