Redshirts

I'm curious about something, and I was wondering if someone can clear it up for me. At the game, I saw a bunch of players dressed who are supposed to be redshirting this year. Guys like Darrin Johnson, Martin Guidry, Mike Benson, Ryan Kennedy, Jamar Bey, Justin Rogers, Anthony Barnett, Reggie Carrington, Robert Gilmore, Brent Karrington, Dustin Morton - I'm sure there were more.
My question: why do we dress them out? If we're not going to play them, why not dress other guys, even scout team guys, just in case we need extra bodies because of injuries or something? Surely the coaches wouldn't blow a redshirt year for one of these guys at this stage of the year. If we somehow got multiple guys hurt at the same position, why not have a non-scholarship guy ready to go out there? There's no reason to risk costing a guy a redshirt year. Just counting the guys I listed there (and again, I'm sure there were more), that's 11 guys who weren't going to play, and I assume there's a numerical limit to the number of players we can dress.
Anyone know the deal behind this?
My question: why do we dress them out? If we're not going to play them, why not dress other guys, even scout team guys, just in case we need extra bodies because of injuries or something? Surely the coaches wouldn't blow a redshirt year for one of these guys at this stage of the year. If we somehow got multiple guys hurt at the same position, why not have a non-scholarship guy ready to go out there? There's no reason to risk costing a guy a redshirt year. Just counting the guys I listed there (and again, I'm sure there were more), that's 11 guys who weren't going to play, and I assume there's a numerical limit to the number of players we can dress.
Anyone know the deal behind this?