With MobileMe, you have explicitly signed up for a service who's primary purpose is to share your data. Android is arguably the same situation, though you don't

With MobileMe, you have explicitly signed up for a service who's primary purpose is to share your data. Android is arguably the same situation, though you don't have any alternative so I would actually throw them in the same dungeon as Facebook. Experience teaches us that the only consequences users understand are the ones they desire. Everything else is ignored. So, if they download their Facebook contacts to their phone and this also causes their phone contacts to be uploaded to Facebook, you will end up with some angry users, dialog or no dialog.