im thinking of more when its IN my pocket. Your pocket wont launch apps really, but all your network apps including web apps, would stay on and connected without draining the battery like mad with the screen being on.
It shouldn't launch any applications. The iPhone/iPod Touch uses an electro-conductive touch screen, so whatever touches it has to conduct electricity. That is why your finger works on the screen, but most styluses don't work and you can't use it with gloves.
This would solve once and for all the chat clients disconnecting. Im sure the SDK will bring new chat apps, but for people that want to stay on older firmware it would be nice.
If I understand you right iLock does this. Bypasses the lockscreen entirely. When its "off" and you click on the home button it goes straight to the homescreen.