Every corset should have a bag, this is what I have decided. According to reliable sources (Denise and the internet) rolled up after an airing is the best way to store a corset. But if you leave it out it could get dusty, or have something spilt on it, or any of the infinite number of things that can damage silk past any point of recovery...tea for instance. Therefore a bag is require, a carrier would do, but it really doesn't look like much.
At the Custom Costume Company, I have been made bag lady, I get to make the cotton lined storage bags for all the corsets we make. I've made four so far (missed one picture though), and mostly I use the fabric for the bag that we used for the corset. This means if you glance at several on a shelf you can instantly tell which bag contains which corset.
It also means I get to play around with the fabrics in whatever way I want. I started with very simple two-piece patchwork, but then branched out to triangles, and even a bit of piping, which I hadn't done before.