Overuse of the spoilers tag? [Madoka spoilers within]

Should the spoilers tag be used on posts that are speculative fan creations, like post #1366863 (Vividred Operation)? Maybe it will end up being a spoiler, but it seems silly to tag something "spoilers" that hasn't even happened in the actual series.

It does seem silly to me to label it a spoiler if it hasn't even happened. Of course in this case it seems so obvious in coming, to me at least, that I'm not sure I'd even consider it a spoiler if it did actually happen. It'd be a lot more surprising if it doesn't happen.

Spoilering things that may or may not be spoilers is getting way too meta. Stick to actual spoilers.

We have a Hilarious in Hindsight pool for that sort of thing.