Does this also apply to SA citizen children leaving SA to neighbouring countries or do they still need UBC? And I assume the requirement for UBC into Botswana remains in place?

How will the stop the child trafficking

Go to Mbuzini on the SA / Moz border and see how people come and go across an international border where no port of entry exists. Child traffickers have never needed worry about any documentation never mind a UBC.

Surely this is something that the authorities know? Did they never bother talking to people who actually know how the trafficking happens?