The red headers do look cool - I have two concerns:
  • Users familiar with the site know that you click through red text to a spoiler - so the confusion factor, even with a disclaimer at the top. Let's face it, people don't RTFM
  • Another concern is that we will have users opening the wiki in edit mode in order to see how it was done and inadvertently making changes.
It is a shame we don't have an html mode for wiki pages, or at least Textile.