Pet Peeve - Reply all

Every so often, I would get an invitation from a friend. And the email invitation would include my friend's other friends. And in some instances, an invitee will reply via email to accept or decline the invitation. And in those instances, they would reply all so that everybody in the email list will get their reply. Why can't they just reply specifically to the inviter and not flood my email with emails from people I do not even know. I seriously do not need to know that they can't come or otherwise cause I do not give a damn.