My feelings entirely OverFlare. Reading about your BA flight, well done to my easyJet flight from Bilbao-Stansted recently where the cabin crew did an excellent job getting a mother and her two under sixes on the same row by politely requesting passengers to voluntarily move to other seats.
This safety issue is presumably why easyJet offer free priority boarding to families with children under 10 years old. (We didn't know about this until we told when we got to the check-in desk - glad we didn't pay for the privilege up-front!) Do any other airlines offer this? Just curious.