Obviously, if your outdoor nuptials take place late in the day, the sun will be well past its peak damage potential. However, if you plan to wed anytime in the morning or afternoon, you might do your guests and their skin a favor by providing sunscreen to slather on as needed.
Be sure to give them a nice variety to choose from, particularly options that are designed for children, babies and people with sensitive skin. The spray-on versions are more expensive than traditional lotions, but they go on much more easily and quickly. Just make sure that the cake is placed a safe distance away … unless you enjoy a little SPF in your frosting.