For questions that require answers to be backed up by equations, empirical evidence, scientific papers, other citations, etc. Review the tag info before using this tag, and flag your question for moderator attention once posted to have the hard-science notice added. Consider alternatively the science-based and reality-check tags. Avoid using this tag as the only tag on a question.
I've noticed that, (and I myself am guilty of this) many questions tagged reference-request don't provide a reference in the answer, only speculations, which essentially nullifies the point of the tag. I propose that we change the tag wiki of reference-request to something similar to that above.
(As a bonus, Worldbuilding has a custom notice set when adding the hard-science to your question reminding you that you should only use the tag for questions asking for scientific papers in the answers.)
What are your thoughts?