I do not call, unless it's a close friend. But, I always make sure to bring extra goody bags. These usually end up going out to younger siblings, but I would hate for an invited guest not to receive one because their parent did not respond. I have actually responded twice to some parties via phone (because I couldn't remember if I had RSVP'd or not.) But then again, I have also found invitations, two weeks after the date, buried in my son's backpack. I guess it goes both ways.