geni wrote:
The problem is only partly due to the spoiler template. Most easy to get at reviews and plot summaries will also tend to protect spoilers. The upshot of this is that for less famous examples it can be quite hard to find a decent citeable sources that discuss the media in the context of the spoiler.
For fiction one can at least go to the primary source for any given spoiler material. Even if one cannot find any reviews anywhere that say who Valen really is, one can still {{cite episode| title=War Without End| season=3| number=16 & 17| series=Babylon 5}}.