Don't they move around planets and suns, regardless? I'd say they move in 2.5, so to speak. They can stack and there is a difference in elevation, but even so, they all stay on relatively the same level.

I think I may have taken a shot that doesn't really portray what's happening- those frigates aren't just that high- they're in the middle of the sun, as you'd see if you were to look dirrectly from above. I see I left that out. My mistake.

Huh. News to me! I've only seen ships circle them, and when I hold down alt, it looks a rim around the sun is a no-go zone.

I don't know why I had that misconseption. I could have sworn nothing has ever moved threw a planet. Rather embarressing, actually. I've been playing since before Entrenchment.

The only reason it's an exploit is that you can't place stationary defences in 3D.