I've never heard anyone complain about Sage factory rods not tracking properly, or not casting a line in a straight line despite Sage not splining its blanks prior to wrapping the guides on them. Perhaps having the guides on or exactly opposite the spline only matters when casting very long distances.
To add even more to this subject of what is the correct way to line up guides, when a person casts a fly rod he more often than not is not casting with the guides exactly facing the direction he is casting. In other words, on nearly every cast a person has the rod rotated either to the left or right of the axis of the guides. This includes the best tournament distance casters in the world.
Therefore, if having the guides on the spline or 180 degrees from the spline was so important wouldn't making sure you always have the guides exactly facing the direction he was casting, especially when casting maximum distances? However, the very fact that almost always the rod is rotated from the axis of the spline when making a cast would seem to negate the need to have the rod splined at all.