I've noticed a few times when I have hollowed prims with transparencies, that the face rendering order is occasionally done incorrectly.
It seems to me that to the inside faces of a prim should NEVER be rendered AFTER the outside faces. everytime I observe an error in the order, it seems that an inside face has been rendered after the outside faces.
It seems like a simple ordering rule, and I can't think of an exception, at least until this new flexibility feature, and I'm still not sure if it could apply.
Just thought I'd drop this simple feedback here.