I think stepping in and 'engaging' with children is something I'll steer clear of after a recent incident at the park. Two small girls were fighting over a scooter and were really screaming st each other with no parent in sight it seemed. Their older brother ran over and was actively encouraging them to start hitting each other. All the other parents in the playground were looking fairly horrified but no one was doing anything. I decided to walk over as there was no mother or father coming across to them, and it wasn't obvious who they were. All I said to the older boy was 'can you go get your mummy please'. By me stepping in the girls had stopped fighting. However i turned around to see the mother now right behind me, and I explained they were fighting etc. She said ' I want them to sort it out between themselves'. Obviously she was ok with them punching each other in public. She was annoyed I had done something but they were around 3 or 4 years old. Now I just look the other way. Unless I know the person, I wont step in from now on.