If someone does /g disband, nothing happens except a message pops up basically saying "Doing this will completely delete your guild and remove all members, are you sure you want to do this? Type /g disband again to confirm."
Reason for this suggestion is I realized that if there was a lectern that had a "click me" text on it with the command /g disband on it, that would delete the guild completely (and that would suck). Requiring a confirmation would stop this and also make sure people don't accidentally delete their guild for other reasons.