Child-free weddings are a controversial topic as many parents feel it's rude to exclude children from a family celebration, especially children who are closely related to the future newlyweds. However, if a couple specifically asks guests to come without their children, many parents still feel like their own children should be able to get a special pass, especially if they cannot find alternative childcare. Most weddings are formal events during which there aren't many things for young children to do, and worrying about quieting a screaming toddler while a couple exchanges sentimental vows is not an ideal wedding day for most couples.
Ultimately, the decision to have children be a part of the big day is up to the couple getting married, and guests attending the wedding need to either abide by the rules on the invitation or choose not to attend. Bringing children to a wedding that specifically asked for no children is disrespectful, rude and asking for a bridezilla-level scene.