I believe that everyone noticed that. :-P For classes capable of calling pets to help them do the fighting, the pet is viewed as an extension of the character, therefore there will be no difference between killing a mob without your pet active compared to killing it with the pet active.
The only thing is that if you do NO damage to a mob whatsoever and simply let your pet kill it from start to finish, you gain no xp, rep or honour... this was introduced in mid-Vanilla to curb AFK grinding.