Well, I think there's probably enough people willing to hound the forgetful people out there to tag their posts, but you don't have a co-mod who could give you a hand with this? O.o Usually pretty active communities have at least two mods, just so one person isn't stuck with all of the work.

Though I think 'tag-your-post-or-you're-dead' might be a little too harsh... *IS ALWAYS FORGETTING TO TAG HER POSTS*