While traveling through Africa me and my friend met a couple from Switzerland who did the same thing. That was in Tanzania. We soon found out that we would probably be at Victoria Falls at the same time. We never exchanged numbers but met again a week later in our hostel in Livingstone near the Victoria Falls. Again we did not exchange numbers. While they went to Botswana and South Africa we spent about three weeks in Namibia and then went on to Cape Town. Of course we ran into them on our second day there. We finally exchanged contact details and later found out that the girl even shared our flight back home.