I noticed the same thing this weekend when I was vacuuming it out. I thought it was odd as well. I honestly have no clue if it is supposed to be like that, I just thought I would tell you I have the same thing under my seats too!
I brought this issue up to the service tech when I brought mine into the shop for power steering pump and steering rack, XM preview channel issues, and strong odor at idle. The service writer said the wires were properly in place and that was just the way it is. I think a cover would be a much cleaner install and wouldn't look so low budget!