Plain old forgetfulness

Claire had been gawked at since she had arrived. Catcalls, sneers, cheers and compliments thrown her way for reasons she could not place. Not until a mousey looking girl came up to her and said "Do you know that you're naked?" Claire looked down in response and sure enough she could see every detail of her nude form. Claire's reaction was just as sure enough embarrassment. Not because she was mortified over her nudity, Claire was actually a nudist at home. Her closest friends were aware of her casual disdain for clothes. Rather she was embarrassed because, being it was the first day of school, she would likely be known as Naked Claire.

"I knew I forgot something," she sighed, her head hung in annoyance as she sulked off to first period.