A maximum of twelve people can participate in a Debate (members of the four teams, plus four judges). The Lobby displays placeholders for badges of all twelve participants, regardless of how many joined. When someone enters, their badge will display their name and role. If there is no name at the top of the badge, it means it does not currently represent any members. User Interface section.
When you are the Organizer, you can only assign/change roles to members when they are in the Lobby. The role assignments will remain in place even when a member leaves the debate, for example, because of a network issue or visiting another site temporarily. When they re-join the session, they will retain their role assignment.