Forum Moderators: Robert Charlton & goodroi
So just I ran some inurl: operator tests and I'm not coming up with any positive evidence. If I were forced to guess right now, I'd say they're not using it.
One canonical form (e.g. all lower case) should return the content along with a "200 OK" status, and all other versions of the URL should return either 404 or a 301 redirect to the canonical form.
Be very careful with this.