It would be very useful and possibly necessary on our site to have support for banners to apply on questions and answers. This would help the questions and answer to get proper attention and editing love they deserve. It is in no way different from how Wikipedia handles the same problems.
They could be implemented similarly. Insert this markup inside a post to make the banner appear:
{{Unreferenced}}
, post has no sources/references/citations given at all
{{RefImprove}}
, post has weak or incomplete sources/references/citations
{{CiteCheck}}
, post may have inappropriate or misinterpreted citations
{{Current}}
, post is related to a rapidly changing event
{{Unreferenced}}
This post does not cite any references or sources. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (Mon YYYY)
> 
This post **does not [cite](https://skeptics.meta.stackexchange.com/q/5) any
[references or sources](https://skeptics.meta.stackexchange.com/q/1023)**.
Please help improve this article by adding citations to [reliable
sources](https://skeptics.meta.stackexchange.com/q/132). Unsourced material
may be [challenged and removed](https://skeptics.meta.stackexchange.com/q/1019).
*<sup>(Mon YYYY)</sup>*
---
{{RefImprove}}
This post needs references that appear in reliable third-party publications. Primary sources or sources affiliated with the subject are generally not sufficient for a Skeptics post. Please add more appropriate citations from reliable sources. (month year)
{{CiteCheck}}
This post may contain inappropriate or misinterpreted citations that do not verify the text. Please help improve this post by checking for inaccuracies. (month year)
{{Current}}
This post documents a current event. Information may change rapidly as the event progresses. (month year)
Finally, the "tools" page should have corresponding category pages to quickly get to a list of the posts bearing these tags so they can be fixed by high reputation users and/or moderators.
{*{Current}*}
instead, since that is unlikely to conflict with any other language's syntax (at least none that I know of).