I was just thinking, is it possible to have a position in which the two players conspire to repeat the position? I mean, if someone moves to attack, and a player has several choices and so is not forced to repeat, but his move forces a repeat so that the first player does not lose material/initiative, does the onus fall on the first or second player to stop the repetition? I suppose I've answered my question, the first player since he began the repetition, but it is an interesting to think about.