Rainspiders prey on geckos. One of the reasons they are useful around the house (especially inside) - to keep the geckos under control - otherwise there is gecko**** everywhere - sticks to the walls. It all balances out in the end. We have both Rainspiders and Geckos. I guess the Geckos probably prey on the baby RSs too.
Saw someone getting really flamed on the Spider Club of SA Facebook site yesterday/this morning. They posted a photo of a seriously smooshed Rainspider and asked for an ID, stating that it "had been found by the domestic worker, who had killed it, obviously." (something along those lines anyway). The Spider Club members were furious - one even writing something like "post a picture of a dog roadkill to a puppy club and see what they have to say about it". The post has since been removed - the person who posted the photo was very upset by the response. Folks who like spiders usually LOVE Rainspiders. They are very sweet gentle giants - although I wouldn't like to be the size of a smallish gecko around one.
There are so few genuinely venomous spiders that pose any direct threat to humans in this country - here is an
updated version of Astri Leroy's "Dangerous spiders of South Africa". It is VERY short.