There was a lot of that (a lot) circulating after Katrina, the storm being man-controlled. Definitely some "eyebrow raising" evidence was presented, but nothing really "convincing", at least not to my mind.
But about the election - if there is chaos to be exploited in terms of ballot-placing, counting, etc., it will definitely be exploited. Count on that, just as sure you could count on a massive land grab after Katrina.
An yeah, smart people plan on finding openings. the nature of the openings makes no difference, and a natural disaster is as good an opening as any. If there's mischief to be made, you can bet that the makers are already in place waiting to for their cue. It may come or it may not, but they're there.