When using the "Restore last presence on login" option and setting the presence to "Offline", the presence is set to online again after suspend/resume. I'm not sure, but I feel like the network status reported by KDE's networkmanagement is actually involved here, which changes from offline to online again after resuming, triggering KTP to restore the last presence. As the last presence stored from a previous reboot was "Online", it is set to "Online" again.
I have to look further into that, but some first thoughts: If mission-control is build with networkmanager support (so it knows the connection state) and the connection changes from offline to online it will try to restore the presence. That's what I would expect at least. There is a bug with "Restore last presence on login". If one goes offline this status isn't restored at login, instead the last online status is restored. This is because mission-control doesn't allow to set the automatic-presence to offline. I have some changes locally, trying to solve that, but it's not ready yet. With the above fixed, this bug should be fixed too.
Telepathy also doesn't reliably reconnect when waking up from suspend. Sometimes it works but most of the cases I end up offline when I wake my notebook.
Git commit 9b8f17433a7b14b256c1eb9272186c0f00ab416f by Dominik Cermak. Committed on 31/03/2013 at 19:53. Pushed by cermak into branch 'master'. Stop using mission-control for autoconnect Instead use our kded-module. FIXED-IN: 0.7.0 REVIEW: 109807 M +14 -26 autoconnect.cpp M +6 -4 autoconnect.h M +3 -14 telepathy-module.cpp http://commits.kde.org/telepathy-kded-module/9b8f17433a7b14b256c1eb9272186c0f00ab416f