Maybe it's prudence, maybe it's something else, but I used to follow in trace behind the tracker, assuming that if there were to be a snake, he would see it. Then I heard somewhere that snakes usually bite the second person.....

That said, the only snake I ever saw in Africa was crossing a road with his head well off the ground. I asked the PH what it was, and he said a mamba. I was a little reluctant to dismount from the hunting car after that, but I got over it.