I agree unidan is not the rule but there have been many others like him who use sockpuppets that get caught pretty quickly. Happened to a high karma EarthPorn mod who apparently only upvoted himself 4 times.
You simply do not hear about them because they are not reddit famous. I used to be very active in reportthepammers so have seen many fairly sophisticated tricksters and spam/upvote rings that got caught. Coordinated new, no karma accounts are easy to spot. It gets much more complicated than that.
My main account, which I used to mod a couple of defaults and a bunch of others with and that's about it publicly, was banned after I started privately raising shit about the way they were treating employees. Not even vote manipulation. They didn't shadowban me but changed my password on that and a couple of accounts I was using through different IPs (but were obvious sockpuppets). I have never heard of that happening before or since. I didn't mind though; I was just pushing them to see how far they would go instead of quitting quietly. So it can happen to anyone.