A valid team consists of two or three members, as appropriate to the format. A team is identified by the individual registration information (Wizards Account) of its respective members and all teams must provide the Tournament Organizer with the full information when registering for the tournament. Individuals may be members of more than one team, though not during the same tournament. If a player drops from the tournament, the entire team is dropped from the tournament. If a player is disqualified from the tournament, the entire team is disqualified from the tournament.
Teams must designate player positions during tournament registration. For example, in a three-player team tournament, each team must designate who is player A, player B, and player C. Players retain these designations throughout the entire tournament.
When two teams are paired against each other during the course of a tournament, the team members designated as “player A” play against each other, the team members designated as “player B” play against each other, and so on.
Team seating is less important than making sure they play the correct opponent from the opposing team. If team member C would like to sit in the middle then that is fine, as long as both teams’ Cs are in the center. Teams should never intentionally scramble their orders mid tournament.