The question is explicitly about a situation when two or more players have the same number of knights in a closed city.
The instructions say: "In case of a tie, the tied players each score the points.". So, the question is how many.
Let's assume the closed city is worth 10 points and is being closed during the game. Should all players get 10 points (each player) or should they get a split (5 points for each)? Or maybe any other way to count those points..