Actually, I think I got the idea from some of that 2x2 wiring with the 2 coax and 2 CAT5 cables. The best possible reason I could come up with as to why I ran the extra cable was in case I wanted to feed a signal from one room back to my wire closet with some type of signal on it that couldn't have been run on the primary coax. My primary coax cable carries pretty much every channel from 2 through 700. With the gaps wherever my cable company puts them. So if I wanted to send a modulated signal back through the line I'd have to change it's frequency or put it on an unused channel. Easier to use a seperate coax.

No, I'm not an installer, wish I was, but working on becoming an electrician, still have to get through school though. I've been doing wiring and home theater stuff since I was a young teen. Bought my first stereo system when I was 12 from money I made mowing lawns (And it wasn't a little shelf system either). I've just been hooked ever since.