Planet rings can be considered so thin that ships' shields even when low in energy laugh at them.
I like that! The particles are very small and the layer is so thin that ships can safely and routinely go through them.
You could even put a small number of boulders or asteroid shards in them to represent bigger chunks of the rings.
(Can't do too many because of Oolite max unit limits.)
And also do an asteroid at the edge to represent a shepherd moon or source for ring material.
I thought about doing that but the difficulty is that as I mentioned before the rings are created via a shader and are not a 3D object. So as far as the game is concerned, the rings are actually a square plan intersecting the planet (a transparent canvas upon which the shader draws the rings). The problem is that there is no way of knowing where the rings are outside the shader, and so I can't add anything to be on the rings since this object might be already further away or much inside. I think I will just leave it as it is now.