Sneezing powder is kinda funny in small groups. larger ones, like parties, can cause crashes and freezes and generally irritate everyone. Maybe make it so that using it causes the user to lose quite a bit of energy and lots more each time he/ she does it. I might be making a moot point- never actually used it myself, so idk if it already costs energy or not, but it seems like something that should punish the perpetrator as well as the group.