I dont think that many people who know what they are doing with an AO ever leave it on infinity, it should be on 200yds as a default, just like putting your saftey on, when you have to take that long shot then you change it, and since a long shot almost always give you a great deal of time to adjust, it works out perfect. When you finish you shot you put it back asap, to prevent situations like the ones you have encountered.
