You are allowed to make their powers go haywire, and there can be a way, be it Initiative manufactured, fluke of the draw manufactured, or other PC provided, to handle them from going totally crazy. Let the mods know if you will want an Initiative manufactured plan of action!

As far as guidelines, it's the usual -- no deaths or werewolf turnings on anyone who has not been consulted and filled out the death form on the associated canon updates & deaths page on the main community. Allowing people to have access if they want it! So generally making an open OOC call out post for plotting when you decide what it is you and your cast (or fellow werewolves) want to do!