Ok well i have been killed by fall damage numerous amounts of time by People who dig strait down!!!! When out in the wild i go out and kill creepers and skeletons because i don't have any other way of getting xp........ I find myself getting shot or blown down or even lagged out down a hole of 1 block killingness... This method should be banned!
We cant actually stop players from digging straight down, its their choice, the best I can do for you is to tell you to try your best. When you first get minecraft, you probably figure out that your not supposed to dig down. My opinion is, people who do that, aren't exactly the the smartest person in the world...
I don't quite agree. When I need to get to layer 16 fast, I usually get a bunch of Stone Picks, a stack of ladders and straight down we go! If I reach lava, tough luck. If I make it in one piece, I usually make a water puddle for falling miners. It has nothing to do with intelligence, it's about time efficiency.
