<p><em>(Turning my comment into an answer)</em></p>
<p>Nearly half (13/22) have either <code>[sc]</code> &amp; <code>[ci]</code>, or <code>[sc]</code> &amp; <code>[ss]</code>.  That's prima facie evidence that it's seen as strongly related to those tags and just adding some nuance in the OP's mind.  The others I'd have to look at, but I strongly suspect something better could be found in each case.  I think we should remove and/or retag them, and then <code>[sc]</code> will just disappear.</p>
