I had to practically beat people to get them to send in their cards!  Talk about frustrating!!!  What is so difficult about sticking a pre addresses stamped envelope in the mail?!?!?!?!  FI's family was awful as well as a lot of my coworkers.  We barely had 1/2 on the due date.  You are not alone!!  Now I have either received them or talked to everyone so my list is complete and I am now working on the seating chart. =) uggh!