I just got off the phone with Disney Dining, (like 30 seconds ago) and we did have to add our infant to our reservations for Dining. I wasn't sure before reading this thread because I don't ever remember doing it with our other kids, and being that this little guys isn't even born yet or have a name. But I can see how he would/could take up a seat at some restaurants. So we added him and didn't have any issues with times or places of our reservations not being able to go from 4 to 5.