Excuse me for jumping on the band wagon that is your conversation. But I think a school should be allowed to opt out of managed ICT because there is a good chance it will strongly affect the ICT teams lives.
I work in a small school (600 students, 100 staff (give or take)) with an IT team of 3, A network manager and two technicians (myself included). If our school was to have a managed ICT system the chances are we would lose all flexibility within our role as a support team. For instance the last couple of days we have been running cables through the ceiling to increase the connection into several offices. If this school was under a managed ICT team then that flexibility wouldn't be there. We would have to request permission from central and wait for a response, just to run a few cables to help out some colleauges. Yes new equipment would be nice, but not accross the whole school.
Not only that, there is a good chance the Network Manager will lose his job, or have his job turned into a technician. And from what I have heard they will reduce the ammount of support in a school anyway.