+1
This functionallity could be use even is the group is not moderated.
For example, this could allow members to present them self, with the help of a dialog.

Enhancement #369: Allow groups to automatically ask question to newcomers

• Author: Samer -
• Status: New
• Priority: Normal
• Assignee:
• Category: Group space
• Target version:
• Resolution:
• Tags:

• Alice presses the "Join" button of Group A (she doesn't belong to it)
• A dialog appear: "The group #groupA asks you: Why do you want to join this group? How do you plan to participate?". The dialog includes a Textfield where Alice can write her answer.
• The reply is sent to the group Admins, as the petition of Alice to join the group... and they can decide more informed.

Optional: let groups choose which questions to ask
Optional: facilitate that the admin(s) can contact Alice to request more info (in a wave message)