On Skeptics.SE and Politics.SE (that I know of), they have banners for questions and answers that pertain to current events or the need for citations.
##Examples of Other SEs
Some of the information contained in this post requires additional references. Please edit to add citations to reliable sources that support the assertions made here. Unsourced material may be disputed or deleted.
(Source)
This question is about a current event. Information may change rapidly as the event progresses.
(Source)
##Proposal
We could ask for a banner on Support for banners? that the mods could apply to both questions and answers that may contain blatant safety issues.
My example text (You can completely reword this; it's just an example.):
Warning! The practices or procedures in this post may have a serious risk of bodily harm. Only attempt these if you are professionally competent in this area. See General Safety Guidelines.