A self-policing system
I think it's a great system to have - and if left to me, I would leverage it, and even try to enhance it to its full potential. Then I would document it, write a book about it and sell it to other families who have multiple children.
The idea is simple, have the children monitor each other and basically tell on each other. We are essentially encouraging the whistle-blowing instinct that is, apparently, built into the genome of every person younger than 10 - after that, I think they learn to collaborate and cheat the system for collective and personal gains - but at this stage, none of them are above that age, so we still have a few years to tweak things.
When we want to enforce a rule when we are not around, we just throw it out there (e.g. "no eating sweets, if anybody eats sweets, Ge Ge will tell me and the offending party will be punished) and the general magic happens. Imagine the end result - "Shannon did this. No Amber starting first. I just copied Ge Ge. No, Gong Gong gave it to us, we didn't even ask for it." Ahh, after a few minutes of letting them talk it out and just open listening, we can easily get a detailed description of the who, when, why, what. And we don't have to interview them separately and/or place them in rooms with one-way mirrors. In fact, I think it works better when they are interviewed as a bunch.
To be honest, it serves better as feedback (i.e. we will find out the truth of what happened) as opposed to an enforcement tool, but the idea is for it to become a consequential reminder, which so far has proven futile - but we have longer term hopes.