A lot of it has to do with the ropes used nowadays. The new low stretch ropes like zing it and fling it, don't absorb water. Old school paracord and the like absorb a lot of H2O.
I've not had rain travel into the tarp via the under the tarp ridgeline ropes.
If it ever became an issue in a rain storm, I'd tie on a drip line.
Ambulo tua ambulo.