Well, I assume most of you responding have never hunted on horse back in the mountains.
Bino's are a must, but... it is very common to use one's scope to quickly glass a high basin for critters when hunting elk, mule deer and bears. There is absolutely nothing dangerous about the practice... in certain situations.
Should a hunter rely on his rifle scope when hunting wooded whitetail farm land? Probably not, you don't know who is behind the next tree.
Can you glass a herd of Pronghorn on the Red desert of Wyoming with your scope? Sure, completely safe and having the rifle up is an added advantage if you need that split second shot before the herd hits 60mph.
Worry about other hunters in this situation? Any hunters for miles around are going to be more than evident, with their blaze orange and vehicles!
So the answer is - It depends on the situation, where you are hunting and what game you are after.
Please consider these facts before blanketing all who "scope" with their scopes as unsafe and un-ethical!