It's your responsibility to call me and tell me that you shot a bystander. On the other side of the coin, everyone should assume that their fellow players are honorable. If someone says he never heard your bomb go off, believe him - maybe something went wrong on your side of things. This way, we won't have any bickering and arguing over who killed who. The section on bombs and poisons is especially relevant.
Dead men tell no tales, after all.
The Consequences Everyone must take responsibility for his or her actions, and this goes double for assassins. Here are the penalties for breaking the above rules. I may just declare you dead outright. Using a class C or D weapon, or any weapon not in the book which I haven't approved, is death for you. Either way, your intended victim does not die.