What is the 'rule' on kids? We're trying to narrow our guest list down, so currently only kids of immediate family are invited (cousins, neices, nephews, etc.), but...a lot of our close friends have kids and we see the kids all the time, so do we invite them? What about the family that I used to babysit for all the time? My parents just said to put the parents of the kids on the list...but the reason for inviting them would be to see the kids?

I know there is no 'rule' and that we can do whatever we want, I just want to be fair and not raise our guest list by hundreds.