Whenever any iDevice downloads a new keybag with an extra key, it gives the user like 15 notifications that a new device has been added to the iMessage account. I don't think there's a way to suppress this (without releasing a new OS).

I think you are assuming too much about the coupling of the UI. Do people iMessaging me get an alert every time I buy a new iPad?

WINDMILLS DO NOT WORK THAT WAY.

No, but the person being snooped gets a notification.

Why do you assume that?

And apple would only have to make sure, that you get no warning, that another device was added to your keybag.

They manufacture the hardware, design and produce the software, and are the intermediary between all device communication with all other devices.

I have a feeling they could manage.

I didn't mean to imply, that they could not, written it missed my ironic voice-modulation ;-)

I really had thought, that this would have happened long ago, for everybody, and so on. Would not have thought, that this was a problem for law enforcement, as it was with i.e. skype.

The user could detect that, though, so it's a no-go.

Not without jailbreaking or proxying the push connection...

No, by default your device notifies the shit out of you whenever your keybag is modified.

You are confusing the iMessage device activation UI with the underlying crypto operations.

Nobody iMessaging me gets any indication when I get a new iPad and add it to my account, despite all their messages to me now encrypting (on their device) to n+1 of my devices now.