@Vofuro,
I'm interested in what way the tag spoiled you as I don't think the tags, as they are now, are specific enough to fully spoil a development.
This is also why I don't really feel the need for spoiler warnings for tags; even if a tag would spoil a certain element of the story, it says nothing about the who, what, when, or how of the event.
Say, for example, that something like a Horror tag for a title that otherwise is perceived as cutesy comedy title would give away the game a little. that alone wouldn't give anything away about when this shift will take place, why it takes place, or in what way to still be plenty suspenseful. It might even
add to the suspense, by making you expect things to go sideways at any moment.
Maybe it's because my personal enjoyment isn't affected too much by advance knowledge, but I find the current tag system to be too broad to say anything more about a title's specific content, besides generic genre. Especially if that means expending the effort to programming this that is better spent on something with a more larger use-case.