From people in the country I've heard that there is often a lot of violence that spills out of the slums around election time.
Citation? The only thing I've heard about are "service delivery protests" that happen in townships, usually due to internal power struggles in the ruling party. The worst effect on the average middle class person, is that a road next to a squatter camp or township that they commute on may be blocked with rocks for a few hours, before police clear the scene.
South Africa does have a relatively high rate of violent crime (and a trend towards organised crime) and a corrupt ruling party.
But the people you are speaking to are exaggerating, and could be a bit disaffected, and are probably not the most reliable sources of information.
See that's where you lack perspective. In safe countries (like here in Australia) you can name any suburb in the country and I'll go for a stroll at 3am with no fear for my personal safety. Why? Maybe I was out drinking and I'm catching a bus home.