The teacher gives direct instruction to the class. She then provides specific instructions for an activity. Students are being loud and not paying to much attention to the instructions. The teacher warns the students that now is the time to ask questions. None of the students have questions. They begin the activity.
Students continue to be loud and disruptive. Some stand up and ask the teacher for instructions because the don't understand what they are supposed to be doing.
The teacher is upset and calls everyones attention. She uses group contingency holding the class as a whole responsible for the behavior of any and all members of the class. She then reminds them that the whole class must finish the activity to go to recess. If they have any questions they should ask eachother.