If everyone agrees that it's cool when we start up. This is the answer to many, many, many of these kinds of dilemmas. There's a certain commonality of expectation that everyone needs to have before the first die is rolled. The DM can accomplish this by having a GOOD list of rules about what's acceptable behavior. A thread with a checklist of such behaviors and actions might be helpful.Do you allow players to kill each other off, or otherwise freak with them?