I had an opportunity to photograph an "All White Party" recently and it caused me to do a bit of research on the history of these events. Often associated with wealthy people gathering in all white attire, I was interested to learn that it appears to have been pushed by a frenchman named François Pasquier who wanted to have an event named Le Diner en Blanc. The requirements were simple. Wear formal white attire, be able to enjoy good food and wine and even better company. Guests were expected to exhibit elegance and proper etiquette, so it's easy to see how this is now associated with wealthy gatherings.
The event I attended was located at Lake of the Ozarks (the famous setting for the show Ozark) at the home of a local business owner. The attire was, of course, semi formal white and it was all about food, drink, dancing, and fun. The hosts were gracious and easy to be around and their attendees were all kind and welcoming as well. It was a great event and I would happily do more of these in the future!