You were replying as I made an edit to note that I personally wouldn't do it if the cable contacted the frame. If it's only barely touching, I'd be surprised if it did anything worse than scuff the paint, but I'd prefer to not even do that.

As for crossing the cables in general, I'm sure you can find references on these forums. Or for another arguably more reputable source, you can read about it on Sheldon Brown's site. It's listed on the following page under '"Criss-Cross" Cables':
Cables