SI date didn't make a difference and wouldn't have made a difference in the ending. Brad saw and was having problems with Chantal's temperment and over emotional nature before the SI date. Most important his feelings and showing her favoritism started from the beginning long before Anguilla. And as much as people would like it to be the case it was not solely based around her child or pity over her tragic story. Brad was into her and had feelings for her before they ever had their 1st 1-on-1 date. Before he ever knew she had a child and a tragic fiancee'. They had a 1-on-1 on the 1st group date that we never saw that he mentions in their 1-on-1 talk at the 2nd RC cocktail party. It's why he was so happy that Roberto & Ali said she was genuine and gave her the early rose becasue his interest was already there and feelings started. It's why he was fumbling his words in that 1-on-1 RC time the same way Ali was at the very same point with Roberto during her season. He never knew about her kid or her fiance' Ricky at the point. Finding about both Rickys only made him realize that things weren't going to be as easy as he planned because he would have to tread carefully to get Emily to be his. It was why he was so relieved when she finally told him on their 1-on-1 about Ricki & Ricky. He was so afraid that his initial opinion that she was th eone was wrong because she kept deflecting his questions. When he found out about her tragic past he realized why she had been holding back and that she was even more than he thought she was. Even more of what he always wanted.
Chantal would always have the same personality and would always be the person he had fun with and some chemistry. She was a backup if things didn't work out with Emily. What happens on the Bachelor is no different than what happens in real life. a guy dates two girls casually and then something happens where he develops more serious feelings for one. And the other one he feels less for as he gets to see her personality in situations or those feelings never progress past the casual. Then, he dumps the casual girl to get seriious and exclusive with the one he really sees a life with. It's life. It's dating on tv or off. Producer setup dates or real life dates, it's the same when you get down to it.