Quite an interesting rule : if poster A and B answer each other 3 (4? ok, 5) times, without anyone adding comment, the discussion is reputed at a dead-end and any additional answer by A or B will be deleted. Unless C contribute to it, than A and B will have three more tries.
Knowing that, A and B will have to concentrate their advice in their first three posts. And C will have incentive to contribute only to restart the discussion willingly.
Problem is, technically, the forum would have difficulty to detect three successive exchange between two users without other contribution ?