Shambles, keeping a thread open does not in itself use bandwith.

If there are for example idiots determined to refresh every Bush thread thats ever been, perhaps bandwidth could come into it, especially if others started reading and replying (knowing MC, most likely to complain to the idiot doing the refreshing). Overall, I would still think it would be admin/moderation but I don't know if it could reach points where bandwidth and other resource issues started to hit. I wouldn't expect an admin to wait around for say 200 old threads to gain posts like "f*** off guest" to find out or to want that degree of "clutter".