Some parents reacted vocally in the press. The main objection appeared to be difficulties with seating families together if you book late or fail to preseat, though some families just resented the fact there might be some controls on them. Experience has shown that, while the majority of families travelling are considerate, a vocal few expect every rule to be bent in their favour.
The public view is different. A recent survey, quoted by the BBC, indicated that the majority of British travellers support child-free flights. In August Tripadvisor found that a third of Britons would gladly pay extra to travel by air with no children present.
It would be a very rare flight that would have so many families travelling together that the 14 reserved rows would in any way restrict the availability of family seats, or impact the profitability of the airline. Children travelling on flights are quite a small minority.
Problem with their “quiet zone”
It is entirely a matter of physics that the noise of the intensity of a screaming child is not going to stay confined to the “family” section of the aircraft. This, despite the intention to use service areas and toilets as a “buffer area”.
By way of anecdotal support for this: I recently travelled in business class on Emirates (we think they overbooked economy and pushed us there to make room, because it was just on one sector of our four-leg journey). There were no children in that section. However, there was an extremely noisy baby at the front of economy (supposedly buffered by the service area and toilets) whose loud caterwauling entirely precluded any conversation, or sleep without earplugs, until it bawled itself into exhaustion.