The adult only flight I take absolutely no issue with...dictating where I sit because I have children with me on an "open" flight; I have a major issue with that! With that said, if there is an option to have a "family friendly zone" on the plane and we are given the option to choose to sit there, then I would be all for it, but to dictate based on the fact that we have children is obsurd...for example, we have an 11, 8 & 1 year old...if it was mandatory for families with young children to be in a certain section of the plane would we really have to split up our family when flying & have one parent with the 1 year old in the let's say 4 and under area & the other parent with the two older siblings?? We also have flown quite alot, my oldest flew in a plane over 24 times by the time he was 2 years of age & I can tell you his manners were much better than some adults I've witnessed on planes. Did we have to teach him how to behave on a plane??? ...ABSOLUTELY! Did we get complimented on his behavior??? ...ABSOLUTELY!
Sooo, if given the option to have a family friendly zone on a plane, well I think it is a great option. I also think that having an adult only plane is a great option, but in my humble opinion, these things should be options...only!!!