Well she didnt want to win, it might be for a number of reasons perhaps her money was on the eventual winner or more likely she wanted to win this horses next race at a good price and a reduced weight.
That's the most obviously stupid display of stopping a horse I have ever seen! Given even an average ride the horse would still have won by 2l. Instead the daft girl endangered herself, her horse and the 2 next to her when she broke jaw and flew sideways. Throw the book at the eejit.
At the lower levels you would do better coming in second - your horse is always winning money, you are not running your horse hard so you can race it more, your horse isn't being forced up in class where it could loose. I know on the harness tracks in America you can make $1-2000 a week by doing this.
But the whole way round you can see she is not riding to win - I am sure she will get some days!