Also correct. Even though a member may log in using their account at another service to identify them, that service won't have access to Groups.io.
Although, as in a recent case for me, I Direct Added a member using an email address they provided.They went to the Groups.io login page and saw the ability to login via Google and promptly did that with an different email address thinking the two would be connected in some way.? Groups.io just created another account with their Google email address that was not connected to any group.
Andy
Andy Wedge