The iPhone 3GS on iOS 4-4.0.1 has a whole other problem whereby you get the phone rebooting after 5-15 min of an out going call which is not dependent on any third party app running in the background and can be easily verified.
There is a 56 page thread on Apple Support Forum , with 828 replies which are being ignored by Steve Jobs.
http://discussions.apple.com/thread.jspa?threadID=2471090&tstart=0
This is not acceptable and not the kind of Apple product we want. Did Apple do any proper hardware testing on international networks where the problem seems to precipitate the most. Maybe if they did bigger and wider international hardware testing they might not have as many issues as they're now having. There is a very significant missing feedback loop here somewhere in the industrial design process.
Let's pray to the computational nirvana at the end of Mr Jobs nose and hope the iOS 4.1 update currently in beta testing resolves the issues. There is no more room for errors now or else Apple faces international prosecution as well as internal US prosecution.
We hope Jobs can get directly involved and it's not just his PR team spinning the stories and getting it very wrong. They have iPad heat issues to sort out too, and MacBook Pro GFX card meltdown, has Jonny Ive got a problem with fans and air vents/grills?
Cheers,
Asam / caMMac