The blind fanaticism for Serena bothers me so much. Does anyone here have any video link that shows the same view of the lines-person? If you think you can positively make the call a foot-fault or not a foot-fault without solid evidence, that's just arrogant.
Now, I'm going to hesitantly trust the lines-person's judgment on this. She was put there for a reason: the officials felt she was qualified enough to be put there. She's the one who has first-hand experience and has the best viewpoint. She may have made a mistake, but none of us can say she has unless we have something definitive.
If anything, I applaud that judge for making a call, sticking to the rules of the game to the very end. Rules aren't made to accommodate a player when he/she feels the need to be. They are there to test a player from the very start to the very end.
If the rules are bent for players just because a game goes a certain way, then what's the point? That's like saying I should be allowed to cheat on certain school tests because they were tough.
A grand slam semi-final or not, it's not about what you think, it's about what is fair and true.