It seems that Pairwise Dissolve does not behave the same as good old Dissolve. When polyline features that share endpoints are dissolved with Pairwise Dissolve, while they will dissolve into the same feature, they become a multi-part features even though they are contiguous.
If one wants non-contiguous multi-part polyline features they'll have to run Unsplit first? Seems to defeat the purpose of Dissolve.
