"I'm suggesting that the main charge people are getting out of venting on this thread has very little to do with actually solving any existing social problem in South Africa. It has mainly to do with people getting some transitory emotional satisfaction out of imagining something really nasty happening to a rapist."

Well, that's something you imagine to be the case about others. I'll say straight up that it doesn't apply to me. I don't know about others here.

If I were in a place where there was a great deal of danger that X could happen, I'd simply do whatever I could to minimise that danger.

I don't think the Rapex is a perfect solution, but it's an option.
South-African women will have to pay their money and make their choice. I'm happy they are now able to do something to protect themselves and it'll be interesting to find out how valuable or otherwise they feel the device has been to them, in a few months or years time.