Having empty chairs across from the bride and groom is a Scandinavian tradition. The signs aren't necessary, guest just know that they are invited to come and chat. This is a simple way to take the pressure off of the bride and groom to do a receiving line or make it around to every table to greet everyone. This way the newlyweds can actually sit and enjoy the meal and it's up to the guests to say hello...What a great idea!
Fun outdoor playspace, while it's great to have space to just run around, outside time can be unproductive and lead to lots of tears for some kids if they don't have enough to do. Just as stations and the environment are crucial for a quality learning space inside, they are just as important for the outdoor classroom.