I tested this and it works! Nice one. 
Another query that might be useful is the pending invites. Admins might like to know what their users are up to with the invitation system.
This query however provides potentially valuable information for community building. I wonder if it could be implemented as a plugin so it’s more readily available. One idea would be to add it as an item on the groups activity menu, so you can see who in your group is doing the most inviting. Permissions could be set to allow only staff or only group members to see it.
