One vial of antivenom is seldom sufficient. Then you need to cater for potential anaphylactic shock when you administer it, and you need to have the right antivenom at hand, and you need to keep it refrigerated (and have it close by, remember...).

Complicated.

In addition, I have very rarely heard of someone dying of snakebite on safari. Actually never heard of a client bitten to death, although I'm quite sure that it must have happened.

I am much more worried about getting shot by a client, which unfortunately happens relatively often............. I have witnessed ADs and hair-rising behaviour quite a number of times, luckily without bad consequences so far - but enough to keep one on high alert whenever he's around unknown people toting a hunting rifle outdoors.