As you may know by now, I hate spoilers. I am also pretty sure other people reading the series hate spoilers just as much as I do. I think that if in the boards discussing the topics should have something like this.
EXAMPLE: Violets hair ribbion (TCC ch. 5)
If all the topics did like I showed up there it should slow down the amount of spoilers.
If it weren't for the fact that the series ended three and a half years ago, I would agree with you. As it is, there are strict spoiler warnings in place immediately after each major book release, because most forumgoers buy the books as soon as they're available. There's not much we can do for people who came to the series later on.