The notice has obviously a general text because it must be used in many places, on any post and on any SE site.
You are free to open a thread on Meta.SO if you can think of a better wording - I've done so myselfI've done so myself for different reasons!
However, the comments on your post are much more specific than the generic blurb:
@LarianLeQuella: Does original research count? – Mehrdad Jan 13 at 21:20
1
Only if it was published and peer reviewed. :) – Larian LeQuella Jan 13 at 21:22
[...]
There is a discussion on meta that talks about the type of references that are required here. – Larian LeQuella Jan 13 at 21:28
@LarianLeQuella: Never seen the discussion, but I didn't see anything like that in the FAQ or anything. I'll remove it once it becomes a rule. :) – Mehrdad Jan 13 at 21:30
The rule has been extensively debated on skeptics:
it is our fifth question ever on meta!
there are 99 questions about it as of now
it's clearly spelt out in our welcome post
To answer your question more explicitly:
The challenge is not automatically implied. Challenges are manual (and on specific points). In practice it means that someone may call you on any unreferenced points. It's a warning that this may happen.
Your material may be challenged in a comment, in another post, on meta, as a flag, in chat...
It is also a warning giving you fair notice that your post may be deleted by a moderator or the community if it is not referenced.
