This is ridiculous!
I think there are a few rules one follows when attending a wedding that is basic common decency and respect for the bride and groom.
Basic wedding etiquette dictates that no one other than the bride should wear a white dress, guests should get out of the way of the paid professionals like photographers and wedding planners so they can do their jobs, and while everyone wants you to enjoy the open bar, do so respectfully.
What a guest chooses to wear to a wedding shouldn't matter (unless it's a white dress - we already covered that), after all, all eyes are on the bride, right? Unfortunately a woman from New Zealand didn't quite get that memo...