If you are using long traces, is it better to use long back-and-forth
traces, or to use lots of little zig-zags?
Lots of zig-zags means more discontinuities from all those 90 or 45
degree corners. On the other hand, they would be evenly distributed
along the length of the trace, so maybe all you get is a lower
characteristic impedance. Or maybe all those corners result in an
efficient antenna. :-(
Long parallel trombones means fewer corners, but they'd look more like
lumps along otherwise straight lines. Plus, longer parallel runs
generally increase crosstalk.
What about second-order effects; for example, does the little zig-zag
approach allow a weaker wave mode to zip right along as if the
zig-zags weren't there?