For those who must transfer to a domestic flight after arriving at OR Tambo.

Travel Alert: New check-in times for domestic SAA flights from Johannesburg South African Airways has announced that its flights on domestic routes from Johannesburg will be closing their check-in gates 10 minutes earlier than usual, as of 1 April 2016.
This will be applicable to all SAA’s domestic flights on departures only from Johannesburg to Durban, Cape Town, Port Elizabeth and East London.
“The reason for closing flights earlier is to allow SAA to conclude all departure procedures timeously especially those relating to baggage, so that our customers may not be inconvenienced by possibly travelling with their baggage left behind,” says SAA Spokesperson Tlali Tlali.

So rather than the inconvenience of your bags potentially being left behind, you get left behind with them.

Well, at least the baggage thieves will be thwarted.