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Just like the thread says, I think it would be fantastic to know what Global Staff is online. The command could work the same way as /roomauth bolds the online auth of the room.
I think this intentionally doesn't happen because it'd be annoying for gstaff to have another route for people to randomly PM them off the list (can confirm it'd bug me, personally.)
Help tickets can already be used to contact global staff.
Is there other use for this?
It could be useful to ask Staff to moderate a room left without modchat, for example. Maybe other people may come up with another uses for this. But you are right, it would be another way to randomly PM GStaff.