Yeah, this is a convoluted way of stating that a syncopation should usually be indicated with a slider or stack--changes in spacing aren't a given way of reading offbeats. The current trend is to browbeat the player into assuming that just about
everything in a map will be either 1/1 or 1/2, because many mappers hate arranging and spacing hit objects in a logical fashion. In many cases, reading spacing appears to be an ancient and mystical art.
Of course, this concept shouldn't be followed blindly. Sometimes, a map with large and consistent spacing can make it very easy to read offbeats and the chant of the spacing-flouters of "LEARN TO READ APPROACH CIRCLES" makes reading the odd offbeat very easy. Just look at this:
There is a clear difference in spacing around the dotted eighth patterns. Even Charles agreed that breaking his polarity rule can work:
However, being able to read subtle rhythm changes becomes hard during particularly fast songs, ergo one should use Charles' guide in order to make patterns easier to follow. Otherwise, subtle spacing changes in sensibly spaced maps can be good in both [Insane]
and [Hard] when appropriate, as they are a great way of adding rhythmic emphasis, interest and challenge--not to mention, enabling many more interesting patterns to be created. Play 'Ouendan 2' and you'll see what I mean.