Dear Etiquette 101,
My niece is getting married next year and would prefer that children not be brought to the ceremony. Some people have told her it would be rude to put "No Children Please" in the invitation, but I disagree. My wedding video was completely ruined because of a child screaming, you couldn't hear anything but that child's shrill screams and I don't want this to happen to her. She is not getting married in a church, she is getting married in a local banquet hall.
It is not rude to include "No children please" on the wedding invitation. The wedding is a special day for your niece, and she and her fiancé should design it to their liking. If that means no kids—for whatever reason—that is their call. It's their party, after all.
But your niece could soften the blow by offering a compromise. Specify that the ceremony is to be child-free, but that kids can join the reception. Or set up a child-care room near the reception room; kids can be near their parents, but the reception can remain adults-only.
Best wishes, Etiquette 101