• Harry Potter and the Half-Blood Prince (contemporary book and upcoming film)
• Beowulf (epic poem)
• Stargate SG-1 (contemporary TV series)
• Iron Chef (TV series)
• The Breakfast Club (classic film)
• Citizen Kane (classic film)
• Jack O'Neill (fictional character)

• The Matrix (contemporary film)
• Three Billy Goats Gruff (fairy tale)
• Beauty and the Beast (folktale)
• Sawing a woman in half (magic trick)
• Final Fantasy VII (game)
• Codename 47 (game, usage of both {{ spoiler}} and {{ Solution}})

For:

• Useful and helpful to some editors and readers; can aid in article navigation
• A convention/practice that readers (and prospective future editors) would expect
• Discourages exclusion of spoilers by some editors
• Can be seen as a neutral label such as "Theme" or "Genre"
• Avoids needing to restrict information to specific sections (such as "Plot details")
• Choosing to add the tag or not is similar to other decisions in the editorial process
• Are consistent with Wikipedia's mission and policy of being informative

Against:

• An informative section header and Wikipedia's content disclaimer are enough
• Violation of Wikipedia's " Neutral point of view policy", or "NPOV" which should cover content exclusion and inclusion
• What is or is not a spoiler is subjective
• Violation of Wikipedia's " Wikipedia is not censored" policy
• Unprofessional and unencyclopedic
• Organization issue; presents the notion that spoilers must be contained "inside the box" of begin-spoiler and end-spoiler templates