I think there would be 1 big problem with the warning, and that is that is would always slow down game-play. Extra clicks and such. That is, if you meant some kind of pop-ups to remind you, you are doing something that might not be correct.
Or did you mean reminders, like in the screen where you accept a sitter, the rules that apply to sitting are listed, just to remind everyone and that the market place shows push rules or something?
That might be a good thing, the reminders. On the other hand, when playing this game, you are considered to know the rules, which is not a bad thing. That some players do not know know the rules, will never be a defense against breaking them.
The control panel for in-game mods might sound like something new, but that is why you have elders, right? If you can't trust them, what kind of panel would you be willing to trust? The president of Innogames? All rules are pretty clear. Some might need to be changed, but there is no real room for subjectivity of the mods I think...
Could you mail me in-game about what kind of ban you are talking about?