I might be in the minority here, but this seems like it could be a case of the rules getting in the way of football common sense. If everything is smooth and there is no deception, why stop the game and penalize a team when there is no advantage gained? This might be a foul by the strict reading of the rules, but we don't use the strict reading of the rules in a lot of other circumstances like holding, pass interference, etc. Unless I'm missing something in the description, I say just let the players sub out and keep on playing. No harm, no foul.