Collapsed Threads: With 50+ comments on a page, the comment threads will collapse, so lower-level child comments display as a link rather than the full comment; this automatic behavior can neither be prevented nor triggered earlier.(emphasis mine)
That is not true; it is possible to achieve the collapsing early with advanced S2 customization. I've done it before... I don't like when FAQs lie, but just omitting that phrase would make it alright (collapsing at 50+ comments cannot be prevented with advanced S2, so that part is right.)