Jørgen Jakob Friis
Come to think of it... my daughter took Judo for one season. She could have become okay at it, but decided to quit after one season. Mainly because the teacher (a green belt - don't know what kyu) didn't want to be firm towards a couple of young boys who endlessly obstructed the training. Several parents approached after training and said that they would find it okay if she told these kids to behave or stay away - at first maybe a quarantine - later expel them. They definitely did not respect their teacher nor the other students. Really bad thing was that often their parents would stay and watch the training without taking action towards these kids.
I have decided not to send anybody away that I believe can better themselves, but also not to take any c... from these kids. I had one last training who rolled his eyes when I told him not to monkey around fighting with his partner while they were supposed to practice their technique. I got a little strict on him, but I don't want pretend fighting and striking or kicking wildly during my classes.. if that's what they want they can go take up Ameri-Do-Te... (http://www.youtube.com/watch?v=3CGMWlXosp4
It sounds like you're going with the firm approach. If that is true to yourself then that is probably the best course. Kids are walking lie detectors.
I'm probably way too soft on my kids, but I have a very small dojo with only 8 kids in the class, so I can afford to be. I made it that way on purpose because I personally can't stand having to discipline and wrangle 30 kids into doing what I want them to do. I just don't like yelling and being forceful with little ones -- it feels "un-aikido" to me in some way.
I really do believe that there is no one right way to do things. All we can do is our best and learn from our mistakes. In a year or two you will have settled into whatever works best for your group.