One really interesting thing I found about moving out of the US is that this is not always the case around the world. At a startup in the Netherlands we were discussing whether or not we could use a particular tax deduction in a particular way. The wording was really unclear. A colleague called the tax authority, and the person on the line agreed that the wording was not clear. They put us on hold, discussed, and came back that they thought we could, indeed, do what we wanted to do. Upon asking they sent us a letter clarifying.
I could not imagine this ever happening when dealing with the IRS.