OK my comments on this. I have hunted impala and attempted to take a kudu from a highseat over a waterhole.

I voted "Depends" as to whether it is ethical or sporting, which by the way is the same thing to me.

It depends to me - if you sit all day on the ONLY water or have hunters sitting ALL day on all waterholes, that to me isn't sporting. We basically drove around and stalked and tracked game in the mornings and evenings and then sat for a while at the water. We were hunting hartebeest and having pushed them hard for a day or two knew they would have to go to water. And they did, at the other main waterhole, and the second time, just before we arrived.

The game certainly was skittish enough at the waterhole especially kudu which came in, drunk, and left always quickly. Warthog were a lot sillier. They also like to wallow of course. Impala again weren't as alert as kudu.

We shouldn't confuse human behaviour with animal behaviour. A human seeing a waterhole in the heat of the day thinks, what a lovely place to spend some hours. A prey animal thinks, what an ideal place to get ambushed by a carnivore, gets in, drinks and leaves quickly.

Elephants are one of the few exceptions of course having no real predator except for man.

Anyway here's pic to enjoy or nash one's teeth too whichever your preference is