Amish? Seriesly?
1. Every bullet has a lawyer attached to it.
2.If you have reason to pull a gun, you have reason to fire it.
3.If you have reason to fire it, you had better be trying to stop the threat to yourself or others.
Conclusion: Warning shots are stupid, especially when the other person has ALREADY pulled out a gun.
Bullets fired into the air land somewhere.
Sheriff: Stray bullet kills Amish teen 1.5 miles away
_______________________________________________________
It is definitely possible to kill someone from a mile and a half away, snipers certainly try it on occasion. Shooting a gun at a very high angle however, like straight up is very unlikely to kill someone. The terminal velocity of a bullit shot straight up is going to be about 100mph. That is fast enough to hurt but not likely to kill. A gun shot at a low angle is a different story altogether. As long as a bullit is still spinning it is likely to be going faster than 100 mph. The lower the angle the shorter distance of travel. One and one half miles is a pretty great distance for a nine millemeter especially a hollow point. A good review of the problem was done by Mythbusters. Here is a link to their story.
http://kwc.org/mythbusters/2006/04/episode_50_bullets_fired_up_vo.html