Well you guys must have some sick iPhone's because mine never pushes and push is enabled. I don't use mobile me, and I rarely access the App Store on my iPhone. When there's an update, iTunes tell's me and I update from there and I never see the badge on the App Store icon unless I go into the store.
I use MobileMe and my iPhone never tells me automatically when apps have updates. I have to open up the update screen before it will tell me.
I'm sure it's the same way with every iPhone out there but people just think the iPhone app updates are being pushed. They just don't realize they have checked for updates first.