The problem with that is that "quiet" is not used everywhere. It's only available on certain networks and putting a lot of checkboxes in Channel Central for modes that are only available on certain networks can make it less useful overall. It could be added, but I think the idea for Channel Central is a place with modes that are common across all (or at least almost all) networks. It's not too hard to script a custom Channel Central for anyone who wants additional modes or other items that are needed only by them or on certain networks. Just my opinion, of course. I have no idea what Khaled thinks about adding modes that aren't used everywhere to that dialog.
