Daphne had a drawstring bag, containing her wand and other essentials strung over her shoulders as she very carefully left the house. It was easy to sneak out. You just had to make sure no one was watching you. And as a child of 8? It was a skill Daphne had perfected over the years. So she headed outside, dressed casually in muggle clothes.
Besides, Daphne needed something to get her mind off everything. And an outing with her twin seemed just the remedy. "Boo!" she whispered, approaching Daniel from behind.