No, it's in there. You just didn't really read or pay attention towards every wording.
When they say "Please be warned that only those who possess an invitation may attend a ceremony..." , it also talks about the hosts (which are yourselves), and how they must be in possession of their blank invitations as well.
SE clearly has it in writing this time, you guys just glazed over the reading when you signed up instead of reading everything.
It's unfortunate that you both had to reschedule and yea, it's a pain in the butt to do so, but you
should have read everything.