Freestyle: eliminate object X

Aside from using Scenes and comping them, is there an efficient way to tell Blender not to include a specific object (or only include a single object) when it renders freestyle? e.g. I have a large skymap with clout textres. I don’t want freestyle to reveal the edges of the skymap object.

Each Freestyle LineSet supports Blender groups. So you could add all the objects, except your skymap object to a group. Then for each LineSet you are using, assign that group. I did a quick test and was able to exclude an object from Freestyle processing using this technique.