Wedding etiquette is a moving target these days, if it exists at all. Ask any wedding vendor and they'll nod in agreement. The reality is we're well beyond the simplistic days when everyone knew, and agreed to, the rules.
Today is an anything goes culture and this is in part why I believe weddings have become so stressful and in some cases pretty toxic for family and new marriages. Wedding coordinators play a delicate balance between letting their clients have their way and trying to gently push back, hoping the spirit of etiquette comes through the wedding: hospitality and putting everyone at ease because they know what to expect and they know their role.
I have read two books, by two highly regarded "wedding etiquette experts." The information provided by each wedding expert often contradicts itself between experts. One small example...did you know the grooms family is supposed to pay for the flowers? At least according to one top wedding etiquette expert. Some etiquette experts still hold that the time of day should dictate the level of formality and other wedding etiquette experts say that is not true. It can make your head spin!
The problems with wedding etiquette today?
"My day, my way" is the overriding theme of weddings today and that will always contradict the more egalitarian notion of etiquette, which is about social grace, respecting others and being as full of hospitality as you can. Everyone knows what to expect in the land of "pure wedding etiquette", but todays bridal culture is ALL ABOUT YOU, regardless of family, of friendships, of anything but what you want. When we run into problems with our family or friends we immediately run to wedding etiquette books to "solve" our problems. This rarely works.
Wedding etiquette does not address the complexity of family life, of society today, of our hyper individualism in America. Etiquette can not dictate when you should have the wedding, who you should invite, or not invite and why, or whether kids should be invited, what role a stepparent should play, or an absent biological parent. Wedding etiquette doesn't help you with who pays for the wedding, how you manage the complexity of a shared wallet, who to have in your wedding party, how to handle a controlling parent, or even how to write a wedding invitation.
Etiquette frankly doesn't do much good if nobody else knows that is what you're trying to do by subtly including only the names of the people on the wedding invitation, thereby "excluding childrens names" is an unspoken way of saying "don't bring your kids!" Nor does it help if a parent is "old school" and believes they are the host and hostess of the big day even if they aren't paying. Excluding them from the wedding invitation can make them feel really embarassed or upset because their view of the world is set in a different time and place. They may feel horrifed that their friends will think they have lost control of their adult child who doesn't know proper etiquette!