I don't know. It would go directly against the concept of "god's notes" that we've always applied to the wiki. We already have the Nook and the Faction Planning for notes about things that the average user isn't supposed to see, but the wiki has always been meant as a repository of everything from an OOC perspective, not an IC perspective.
Though, just a kinda sidenote, but spoiler tags wouldn't make it so only certain people could see something, Kyle. Just so that they needed to click a little tab to view it instead. Wouldn't really work at all to keep things from common knowledge, if that's the goal. Spoilers are meant more to conserve space or warn people that there's something they might not want to read.