I have a user A and a user B
I have a team created with free plan by user A.
User A created a team board, set its visibility to Team Visible.
User A invited user B to the team, but did not invite him to the board.
User B can now view board, but cannot edit anything in it EXCEPT he can remove that board from team, which is kind of a disruptive action by someone who was not even a part of a board.