AIM buddies switching to mobile without signing off

[mwn3d]

When a buddy's cell phone is signed on AIM, but they are signed on at a computer, their IMs go to their computer and not their cell phone. When they sign off of AIM on their computer, their IMs go to their cell phone, but I am not notified of this switch on my computer. I'm not sure if the actual AIM client notifies users of this switch, but Pidgin does not and it should if it could. It should look like the notification that they have gone away or become idle. "[buddy] has changed to mobile IM." or something.