Last weekend my friends and I had a dinner party, it was relaxed, informal. One if the hosts invited another friend, who/whom we all knew but not very well, and he invites one of his friends and that friend brings his girlfriend.
Now I thought that the hosts' friend essentially inviting two more people was odd and out of line...I have always been taught that I never invite additional people to a party that I am invited to, unless I was told I could beforehand (without asking). What do you guys think?