It is possible to authenticate a user for a conference room from the Galene’s web-front end to this room, although the room has the members-only property set and the user is not a member of the room. It is sufficient that the user is a registered user at the whole system.
After successful authentication the user does not see others, which are already in the room, too. Neither can the user send or receive media streams.
The behaviour is acceptable regarding security, but not straight forward. Users, which are not members may not get authenticated in case of members-only property set.