... you will be spending the day outside watching the ceremony on a big screen, need to take your own food and drink and are actually just spending the day standing in a special enclosure for worthy people that's marginally closer to the castle than the general public will be able to go 
There's some very excited people just been on our local news waving their "invitations".
While I'm glad that they get a day out in Windsor and the chance to put on a posh frock gender-neutral clothing of choice, AIBU to think they are a bit deluded thinking they have been invited to the wedding?