What happens if a guest dies on the way to a wedding?

You can't help if someone gets in a car accident on the way to your wedding. I would hope no one would share this news with you until after the ceremony, at least. That's not the time to share things, as it would ruin your special day. I would most certainly go through with it. It would be a waste of time and money not to. And, by the time people are leaving for the wedding, everything is ready to go. You can't stop life because of a death, especially not something that took so much time to plan.