I feel like a very high percentage of the questions asked here concern plausibility, which is something that's hard to avoid where any kind of fiction is concerned. Some questions purport to be related to "reality", even if they try to "hedge their bets", but in the context of fiction are really about plausibility. Some questions seem to be asked with the intent of eliciting a plausible backstory.
Plausibility is highly subjective, but we can approach it from a general-public point of view. After all, gamma radiation was once a plausible explanation for anything. Nevertheless, a fair bit of conflict seems to ensue when the realistic answer is "that's impossible or vanishingly unlikely", the lazy answer is "feed them some Phlebotinum", and the questioner wants something in between. It would be nice to be able to head off some of this at the pass, as it were.
On the subject of the hard-answer scale as described above, I feel like some perfectly good answer people get marginalized when they are naturally inclined to one end or the other of the scale, but don't get the sense of which end the questioner meant. The hard-science, science-based, and fantasy-based tags ought to help, but the vast majority of these have a perfectly accurate science-based tag that conveys nothing about what they expect in terms of a plausible answer.
How can we be more granular about indicating these questions that are based on plausibility? How can we better filter out questions that require a large, plausible, but fictional, backstory?
Also, can we implement some friendly shorthand for "your scenario is scientifically ludicrous, so stop trying to justify it with some kind of plausible backstory and just write your actual story, which sounds interesting"?