When I was there last June, I can't say as I noted any significant mowing lines narrowing. I would say that they apparently received more rain over winter/spring of 2016, and that effects the rough, dry pasture density out there considerably. But, I'd say that 70% or more of the rough areas are ball-findable and playable. Like Carne, there are some steep slopes into rough areas that a fellow would maybe choose not to go down there and risk twisting and ankle, etc. But, where the breeze blows irrigation into rough and low areas, there are unplayable areas. Not that many as one would think, however. There is a great deal of cart traffic and mowers and such that do leave tire traces in the fescue, which are not a playable issue, just appearance.
I played SHGC that same June week, and the rough there is notably even more sparse and playable. I can't explain that being 5-6 miles up the Dismal R. as the crow flies. Nicklaus course also being a few years more mature, is a bit more dense rough, but mowing lines there also not notably more narrow.
Maybe someone else has a different observation.