Click to enlarge, and debate the strip below the line.

Keith Hackett's verdict

1) The foam line is just there as a visual guide – the final call on whether the players also moved forward as well as sideways is yours. If they did not move forward before the ball was kicked, play on. If you believe they did, award a retake. The foam is a useful introduction and does reduce controversy – though I look forward to seeing what happens when there is snow on the ground. Thanks to John Henderson.
2) Send the defender off – a second yellow, then a red. He clearly attempted to trip the attacker with a reckless challenge. Restart the game with a penalty for the attempted trip: it doesn't matter that no contact was made. In this situation, you cannot also punish the attacker for simulation, as, had he not dived out of the way, he could have been seriously hurt. Tom McKenzie wins the shirt.
3) No. The player has rejoined the game with your permission – albeit briefly. So he is well within his rights to step back – he does not need your permission to leave the field in these circumstances – catch the ball, and take the throw. Just be sure the ball was fully out of play before he caught it. Thanks to Paolo Manini.

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