So I've been using the "guestlist manager" on the my knot profile to keep track of my responses. I've been feeling bad for the last few days thinking that not many people responded YES to our invitations. Today I added a guest response and the number that is supposed to count the number of people invited did not change, so I decided to count them myself. The knot said that there were 40 YESes, the ACTUAL count is 67!
I don't know if anyone did that too, but if that is the main way you've been watching your RSVPs I suggest you take another look.