I can tell your working with architectural drawings. I'm going to say what most will not, and that is that architects are some of the absolute worst when it comes to drawing things precisely in autocad drawings. Snap to grid, ortho on and precision set to whole inches and over ridden dimensions everywhere are just a few of the issues we have seen in the majority of architectural cad files I have had the displeasure of dealing with. Why? I don't have any idea, but it is unfortunately more often the rule instead of the exception, and I would get fired for drawing things that way.
I apologize to those architects that don't do this, if you don't, be happy that you are the exception.
If you are one of those people that do this, don't bother making a defense for it, I really don't mind, we make a huge amount of money creating shop drawings and putting in change orders when the things specified are a physical impossibility and we get to charge to make it work. 