doesn't disable the protocol used to make calls and send sms's..
Sorry you're correct for iPhone - I was meaning iPad. I can't confirm 100% whether it's zero transmissions, but even the little icon changes to "iPad" instead of "Carrier" or "Telstra" at the top when you disable data.
you can shut them off. extends battery life.
Yes and no - 95% of apps are actually suspended when in background. Apple multi-tasking isn't
real multi-tasking like on a mac/pc where the app is still actually running. When you quit back to the home screen, your app gets 10 seconds to tidy up anything before the operating system suspends it. Apple deliberately chose this method to SAVE battery...
All it means on iPad is that the app starts up from where you left off. If the current running app gets short of memory, it starts killing background apps anyway. OzRunways uses a lot of memory so most likely all your background apps will be killed anyway, which is why menu's are a bit jerky loading initially after running OzRunways. There are a couple of exceptions to apps running in the background, like VoIP apps that can specifically be enabled always, but it's not normal behaviour.
The irony is you may be using
more battery by having the screen on every half hour killing apps. If you want to save real power, disable 3G & make email check every hour (or manually) instead of 15 minutes.