The remaining issue why people 'swerve' Comps in less affluent areas, or Comos altogether in favour of Grammars, is that you cannot guarantee avoiding the disruptive element.
It is currently fashionable to do away with setting. There is some educational research which suggests it doesn't help, particularly the lower ability groups. A number of schools are reducing the amount if subjects being set or delaying doing it until later. My cynical head says its to save money during funding cuts but it helps that there's some research to justify it. This kind of thing makes the sharp elbowed parent even more jittery about Comps, even the good ones.
I agree that many Comps now have some great behaviour policies and their zero tolerance approach is paying off. However low level disruption or the threat of it is never far away. Quite simply, in selective schools, there is less of it.
Parents choose schools based on results....and it's true that able kids can do just As well in Comps. However parents also look at behaviour and the cohort and believe that a more mixed background cohort might disrupt their child's education and make them less likely to get the food results, plus most importantly perhaps, decide they want their children to have a more positive and less disrupted experience of school - and that is more likely in a selective school, or if only Comps are available, in a Comp with less social diversity.
It might be the elephant in the room and it might be unpalatable and we might all like to say that all children should equal opportunities for good education and all children should have access to the same schools and really believe it......but most of us don't want our own children to be affected by disruption.....and with the best will in the world and the best systems in place, schools which have large numbers of children from more difficult backgrounds with more challenging behaviour, the experience won't be the same as if those children aren't there.
In reality, people aren't very progressive and liberal and socially inclusive when it comes to the schooling if their children. Having some choice, rather than having to go to your local school has led to lots of 'swerving' to Grammars, to Church schools, to leafy Comps, to independents.....anything to avoid the disruption which can exist. And I don't see it changing anytime soon, or anyone on these threads not doing a bit of swerving themselves. Anti private and anti grammar and anti faith school people sometimes find their principles aren't as strong as they thought and send their kids to the mentioned schools. Others with stronger principles still find they can send their children across town and pay for the bus or to drive them,mrather than go to the local sink school - very very few people really want social inclusivity.
The only ones I've ever seen really go for it were a Church who were looking to really integrate into the local community and make a difference. They didn't just drive in from the suburbs to 'do good' but people moved onto the estates and sent their children to the local schools. It was an impressive sign of principles in action, but it's very rare.