There's also the problem that there really isn't any universal rule for what kind of spoiler requires a warning. Even leaving aside the fact that people in different countries get things at different times, there's the fact that not everyone watches everything right as soon as it comes out. There are people today who are just starting to watch B5, as well as just about every movie or TV show regardless of how old it is. So what kind of discussions require spoiler warnings?
IMHO, anything with a twist ending should have a spoiler warning, regardless of how old the movie/TV show is (although there are a handful of exceptions, like the end of ESB, because the twist is so much a part of our cultural consciousness, that only people who've been living in a cave don't know about it). Other kinds of plot points can be more ambiguous. There are certain things that might deserve a spoiler warning when the movie/show is new, but might not after it's been out for a while.
A friend of mine, who has not read the Lord of the Rings books, but did watch the movies, was quite miffed when, in the spring of 2002, he happened to read the Lurker's Guide page for "Z'ha'dum", and, in discussing the fate of Sheridan and the similarities with Lord of the Rings, [Big spoiler for THE TWO TOWERS] they spoiled the fact that Gandalf comes back to life. Of course, when Steven Grimm wrote those words on the Lurker's Guide years ago, he probably assumed that it would be silly to include spoiler warnings for a literary classic. But you never know. Not everyone has read everything out there, and different people have different ideas about how spoiler free they'd like to be.
