tl;dr: There is a current problem with the Hot Network Questions showing titles to users who would otherwise wish not to use this site. This problem however is unrelated to the way this site should present it's titles. The current consensus regarding spoilers in titles is that they should be used for works that are not extremely new.
--
Regarding the question of spoilers in the title I will quote the current scifi.SE consensus:
Normally we operate on the assumption that certain things are too popular and old to be mass spoil-able. However, if you feel this isn't popular/old enough. Feel free to edit it yourself.
There are just some things that it is hard to ask about effectively without some small spoilage. We are, after all, a site dedicated to answering questions about plots, and the very nature of this is spoilerific.
Additionally, spoiling may not be the bad thing we've always thought it was.
(Source: DampeS8N on Is it okay to have spoilers in question titles?)
Then we have Is there a moratorium on some spoilers? asking whether spoilers get out of date at a certain point, where the highest voted answer states
It's up to the person asking/answering the question to decide.
And additionally quotes Jeff sharing his personal guideline which seems valuable to consider:
I also take the age of the work into account. [...] With TV shows, I try to spoiler big plot points from the current season, if practical.
Both movies and television are relatively easy [...] Books are a different story, in my opinion. Books don't generate nearly as much buzz upon release, so I tend to spoiler important plot points [...] for quite a while afterwards.
(Source: Tony Meyer on Is there a moratorium on some spoilers?)
Now, disregarding meta.scifi.SE discussions up till now presenting the rationale in favour and against spoilers:
Against
- Currently popular question titles are broadcasted all over the network, thus forcing it upon people who would otherwise not use this site.
In favour
- Questions should be searchable.
- Even on scifi.SE itself when asking a slight paraphrase of this question it did not appear in the suggested question list (all other questions except one contained the word "Dobby" literally in their title and thus ranked higher).
- Titles are predominantly shown on Google. The idea of SE is different to a forum or traditional Q&A in that it's meant to answer everyone's question, not only the person who first asks it. If questions can't be found or will be badly indexed this point will be lost.
- A title in general should be representative for a question (that's the point of a title). Exceptions can be made in cases where a work is currently really popular (e.g. current season or e.g. 3 years or so for books). People who hate spoilers that much should not go to a Q&A site as this inherit to the nature of such a site.
Regarding the against rationale I would simply argue the following: This should not affect question titles and instead people who take issue with this should add a feature request regarding the filtering and/or hiding of HNQ on meta.SE and upvote it. This seems like a very valuable addition to the SE network that goes far beyond the issue of spoiler only.
