Setting boundaries

Is there a difference between disciplining children and setting boundaries for them?Interestingly this was the topic of discussion amongst the Primary teachers this week.The discussion began with a concern regarding the bullying by children in the buses......pushing each other,throwing water and not allowing the younger ones to sit down.This had been happening for a long time.While talking to the children was helping to some extent,some had fallen into a pattern and knew that there would be no consequences so wouldn't be bothered.How should this be handled?Does discipline not have a role to play here?Disciplining would be communicating in a serious tone about a desired behaviour which children do not even understand at times.The other way would be to talk and reason with them and help them relate to certain things.Most of the times they do not even need to be told.Seeing the elders around them do certain things,they automatically follow.This is self discipline.Going back to the bus issue,have reasoned enough with the children and some have understood the purpose but what about the others?Here we need to draw the boundaries and let these children know that they can board the bus only when they are ready to take care of the younger ones and not trouble their friends.A sensitive teacher should be able to discern and decide when to draw the line.Freedom goes hand in hand with responsibility and here comes self discipline.When we say we do not discipline children ,it should not be interpreted as we do not know where to draw the boundaries.