I just thought of this… Perhaps we can have a passive alert (that will not be intrusive) to inform pilots and ATCs alike that another Controller is online so this recent Controller doesn’t have to send guard messages… Also, I love it when I have other controllers online with me…
Like perhaps if I take WSSS_GND and WSSS_TWR and he takes WSSS_APP, I can handoff the plane to him but I noticed this doesn’t happen when GND and TWR is controlled by other people while I control APP or CTR…
Perhaps some people don’t bother but I know some like the feeling of having other controllers online together :D