Allolex suggested I share this with the group:

If there is a root node called Spoilers, where all spoilers live separate from the original thread, each spoiler "answer" can have comments and replies, which will not show up in the original thread. This keeps all spoiler related discussion tucked neatly away behind links.

Allolex points out that this departs from the SOP where one root node "contains" the entire discussion. I assume this comes from some ideal of displaying the root node and reading the entire discussion just with a mouse-wheel -- of somehow encapsulating a discussion into a glass box for all to see at a glance.

I would counter that many threads have links outside the original thread. In fact, in a heavy response thread, beyond some threshold responses are hidden behind links anyway.

<tongue-in-cheek>What are browsers for?</tongue-in-cheek> :)