<p>From <a href="http://meta.stackexchange.com/q/71712/184716">this MSO post</a>:</p>

<blockquote>
  <p>The Precognitive badge appears in the badge list on every site to announce the presence of Area 51, and its primary function.</p>
  
  <p>Since Area 51 is itself about creating new sites that don't exist yet, the thought process is supposed to be:</p>
  
  <blockquote>
    <p>hmm, I can't get [the precognitive badge] on this site, but I could get it on some hypothetical future site I might be interested in.</p>
  </blockquote>
  
  <p>Yes! Thus, based on seeing this badge and reading about it, a user is incentivized to:</p>
  
  <ol>
  <li>visit Area 51 (and we provide a handy link in the badge description itself) -- win</li>
  <li>look at upcoming site proposals -- win</li>
  <li>follow likely proposals, which requires reading them and deciding if they have a chance -- win.</li>
  </ol>
</blockquote>

<p>So in conclusion it seems that Stack Exchange knows these badges (or at least Precognitive) aren't possible on this site, but still thinks their presence on the Badges page is a net positive. I'm not sure I agree, but in any case this isn't likely to get changed.</p>