A friend of mine married her husband in a JP wedding, but there were extenuating circumstances surrounding it. She needed to be on her husband's insurance because she needed spinal surgery due to a car accident they'd been involved in. They then got married officially (in their eyes) the following January, and that's the wedding date they celebrate. Those who were invited to the wedding were aware of those circumstances, and didn't begrudge the HC the second ceremony.
In my mind, etiquette may dictate one thing, but I do not believe that it would be fair, or even practical, to the HC if they were penalised for extenuating circumstances just because etiquette dictates that someone must only have one wedding.