We were watching the Mythbusters finale ‘behind the scenes’ special and Adam said, after showing a duct tape trebuchet flinging a fireball, that it wasn’t a spoiler. My wife said it was and I said no.
A spoiler is not ‘something happened in the tv show/movie/book.’ A spoiler is something that happened and gives away a crucial plot point. Telling people that the ship sinks in Titantic is not a spoiler. Telling people that Rose lets Jack freeze and die in the water, and keeps the necklace, is a spoiler.
That’s why telling people that the Death Star blows up is not a spoiler, but the reveal of who Darth Vader is was a huge one. Similarly, it’s not a spoiler that the rag tag band of derpies blows up the Death Planet, but it is to reveal how and why Han dies. That particular plot line hinges on the build up and then the denouement is the choice, the action, and how the death happens.
Spoilers are the scenes that make the story. Everything else is a teaser to whet your interest.