Thanks for all the ring tech, guys, a lot more to it than I'd ever dreamt. I don't build a lot of engines, but do set the gaps apart when I do. It's no hardship, I'll keep on doing it, whether it's necessary or not.
Many large industrial 2 cycle engines (10"-12" bore or larger) have doweled piston rings to prevent the rings from rotating. This keeps the ring end gaps passing over the webs between the ports to prevent ring clipping and port wear.