YABU
Very good friends of ours are getting married in July. We immediately said, "Yippee, grandparents are staying at ours then, and can look after the children", but our friends immediately looked something between shocked and hurt.
They don't have kids, (but want to start sometime soon), and think our kids are wonderful. We attended a family day event of theirs recently, of course we all dressed appropriately and our kids were charming. (Apparently others commented on how well behaved they were, and how nice they looked. (We were the only people to bother to put our kids in something better than jeans and a t-shirt)
Our kids were lovely, but it was still hard work. Basically didn't manage to have a decent conversation all day. There was always another nappy to change, one of them wanting something to eat or drink, wanting to play/chat or trying to climb up a ladder or put their finger in a powerpoint. All perfectly normal behaviour, but there were people there I hadn't seen in years, who I dearly wanted to catch up with and another couple who only knew us and the bride and groom, so wanted to talk to us too.
I'm hoping this couple go for an evening event, so we have an excuse to leave the kids at home. (It's over 1h drive, so can't quickly drop them back at home halfway through.) But was really surprised that people I've known for so long, and know well, would have such a different view to kids at weddings than I do. (My boys will be 1.5y and 4y when they get married.)
(So AIBU to leave my kids at home, even when they are explicitly invited? ;-) )