Opponent copies your moves in daily chess tournament

@Optimissed, that's a different situation.  That's an opponent looking at a historical game you've played and picking an opening line that you struggled with.  That's a legitimate thing to do in daily chess - or even to prepare in advance in live or OTB.

That's a totally different thing from someone playing two games against you simultaneously and copying the moves you play from one game to play against you in the other game.

For example, in the game where you're white, you might play 1. e4.  Your opponent might then copy that and play 1. e4 in the game where he's white.  You might respond to that with 1...c5, and then your opponent might copy that in the game where he's black and play 1...c5 against you.  Effectively this forces you to play against your own moves, and your opponent is guaranteed to score 50% against you.  This is what this thread is talking about.