I think I am lucky - my MG are pretty relaxed, but we do step in when the babies get a little rough - eg hair pulling or a bit of innocent wacking, especially when another baby ends up in tears - and we do say things like "gentle, gentle" (my DS knows what this means and most of the time will softly stroke instead LOL). I think its fine for the mothers to 'politely' jump in, but mostly we dont 'tell the babies off' but distract them with other toys etc, as we do need to teach our babies and children to be respectful of others, even at this age - sure they might not understand it completely yet, but everything sets the foundation for later behaviour.

Personally, I am sick of mothers who say "Don't do that darling" then let their little 'angel' do whatever they are doing over and over and over again while my house gets destroyed, mothers like this dont get an invitation back - sorry! Yes kids need to be kids and muck around, get messy and learn from their mistakes, but they also need boundries - there is a healthy balance in there somewhere