Guest apparently bringing baby to wedding

As a breastfeeding mother myself I understand how it can be difficult to make arrangements to weddings or other events where children are not invited, but if it’s important to us then we have happily made childcare arrangements to respect the couple’s wishes.
Our wedding is May 2nd and my cousin and his wife just had a baby a month ago. We invited them and were told they wouldn’t come by my aunt. Well, they ended up RSVPing. My dad told me that apparently they’re strapping their baby to them and coming anyways without even asking if that’s ok. Website and everything kindly requests to make arrangements.
Heck, my baby is the flower girl and then getting swept away by a sitter staying in our room for the entirety of the event because as much as I love her I don’t want anyone worrying about a baby and to just enjoy themselves.I’m a bit ticked. We have so many friends with little ones that have made arrangements and they’re going to show up and see that there’s a baby there.Mind you- this cousin and I are not close at all. I haven’t even met his wife because their wedding was child free and I had a baby. So I didn’t go.
Do I confront them? Leave it and hope for the best? I guess the part that irritates me is the lack of decency to even ask if it’s ok…