Sadly there is a risk involved with everything we do - as Johan Rebel said, mostly nothing happens.
Over 20 years selling safaris to Africa, I can hand on heart say not once have I or any client ever been harmed. Charged, definitely, come too close for comfort, yip, but fortunately never harmed. However, I could say the same thing about driving - many near misses, many too close for comfort and although never harmed, I know of others that were not so lucky.
There is no experience like being out in the African bush, but they are wild places and there be wild things - that is what makes it so exciting after all.
It is always tragic when anyone loses their life, and no less so in this instance, but it should not stop anyone experiencing the wonder that is nature.