Like I said, I'm probably in the minority. I don't view "fun" and "structure" as two things in tension that need to be balanced. Football is a game, and games are fun. But even a funhouse has concrete under it.
As a coach or volunteer coach, my first responsibility is to the collective experience of the team. And for better or worse, Playground Etiquette 101 is part of any group activity, even at age 5.
If a 6 year old isn't having fun because his i9 coach thinks he's grooming the '85 Bears, that's the coach's fault.
If a 6 year old isn't having fun because acting out and being disruptive aren't tolerated, that's not the coach's fault. That's not even the kid's fault. That's Dad's fault.
If a 6 year old is acting out and being disruptive, and (volunteer) coach never visits with Dad about it and/or doesn't ask Dad for air cover during the other 167 hours in the week, that's coach's fault.
As someone once said: There's no such thing as bad dog; there are only bad owners.
6 year old kids are gonna mess up constantly. But having structure isn't the same as maintaining discipline. At the end of the season, I may or may not have a "disciplined" team. But it isn't about discipline. It's about confidence. It's about having a shared experience. It's about having goals that 6 year old kids can visualize, and, more importantly, are within their power to achieve (since not everyone that age can catch and score touchdowns).
Each season my parting words to parents are always the same:
-- Thanks for sharing your Saturdays with me and my sons.
-- I hope your child enjoyed the ###### out of the season.
- I hope your child learned something from me and the other coaches about competition, teamwork, and the game of football. (In that order.)