I don't see a valid use case here.

If people are foolishly copying bits of an article to a talk page, they should be good enough as an editor to remember how to use <references />.

Added namespace detection to 'MediaWiki:Cite error refs without references category' on the test wiki and enwiki. The automatic reference list on user and talk pages can now be suppressed.

(In reply to Gadget850 from comment #2)

Added namespace detection to 'MediaWiki:Cite error refs without references
category' on the test wiki and enwiki. The automatic reference list on user
and talk pages can now be suppressed.

Strike the above.

Given the feedback on the enwiki Help Desk and Village Pump Technical, I am reopening this.

Please link to the specific feedback on the enwiki Help Desk and Village Pump Technical.

Here are the ones I can find with a quick search:

Wikipedia:Help desk#Ghost series of footnotes following me around and tacking onto the end of what I write

Wikipedia:Help desk#References pasted into talk page encroaching on the next message

Wikipedia:Village pump (technical)/Archive 130#References showing on discussion pages

Wikipedia:Village_pump_(proposals)#Turn off automatic generation of reference lists on talk pages

And now

Wikipedia:Village pump (proposals)#Fix problem with references on talk pages

An idea I added there that I didn't see before was to have the automatic list for be placed just before the level 2 header immediately following the unresolved refs in talk namespaces. That would keep them in the same topic section where they relate rather than falling into whatever the last discussion topic on the page is (or even more confusingly, into whatever later discussion topic did have an explicit reflist of some sort).

Unfortunately, this can't be done with the ParserSectionCreate hook since refs are processed before it kicks in. AFAICT, this would require a new hook inside Preprocessor::expand called when headers are made.
It's also worth noticing that this would be useful for pages not in talk namespaces, e.g. WP:ANI, helps desk, etc. But we can't check a magic word such as __NEWSECTIONTALK__ since they're processed much later in the parse (and it should still work for archives...). To handle these, we would have to e.g. have a mediawiki page where they can be listed.

Change 273520 had a related patch set uploaded (by Cenarium):
Add references list at the bottom of sections on talk page

https://gerrit.wikimedia.org/r/273520

I'm not sure this is necessary at this point. On en.wp we've socialized the use of {{reflist(-talk)}} sufficiently. I would guess other wikis have done similar.

Change 273520 abandoned by Thiemo Kreuz (WMDE):
Add references list at the bottom of sections on talk page

https://gerrit.wikimedia.org/r/273520