A few times over the past year I’ve noticed a nice place where hyponegation (less negation than is necessary to convey the logic of what you want to say) happens: in wide scope negation involving _because_ clauses. Consider:
> It’s not that he didn’t hire you because you were black. They didn’t hire you because you showed up dressed like you didn’t want or need the job and you showed up late.
This sentiment was conveyed [here](http://answers.yahoo.com/question/index?qid=20090921214046AAX1ybM) like this:
> Sweetie…_they didn’t hire you because you were black_, they didn’t hire you because you showed up dressed like you didn’t want or need the job and you showed up late.
Here’s another example (I think; it’s hard to tell just looking at text):
> I don’t like fans from Philly because of the rivalry. I don’t like them because they are crass, obnoxious, and always want to fight.
And I can recall several times hearing the basic form
> I don’t X because A, I don’t X because B.
meaning “I don’t X, and it’s because of B, not A.” One could speculate on why this might happen. E.g., you’ve already started the sentence with main clause negation on the auxiliary (as opposed to a cleft like _it’s not because…_), so to maintain the proper amount of negation you’d have to have a _not_ after the negative auxiliary (_I don’t not X because A_). It’s not quite a repeated morph, but it’s awkward enough that maybe it’s worth avoiding. Interesting, though, because there’s no way that _I don’t X because A_ could be interpreted on its own as _I don’t X, and not because of A_. You need the contrast with the second clause for anything to make sense.