I don't think we can completely discount the small possibility that the S&P might decide that, due to overwhelming feedback from the investor community, they will be adding TSLA in two equal tranches, 50% on December 21, 2020 and 50% X months later.
As an investor, I do try to limit my exposure to the unexpected. I'm just having a hard time imagining that the S&P is going to make the index funds buy TSLA in the middle of a squeeze. While it's possible, it doesn't seem to fit neatly into my worldview.