My bet is also on bugs. She planted them, knowing she would be the talk after her visit and retrieved them later. Even if someone would find one by luck, they wouldn't know, what it is. Clever girl. But really...no matter how well behaved and "small" they are, never call nobles stupid into their face. It's bad practice to do it to anyone, who might have an influence on your life. Especially if she has her own mind and seemingly nothing throws her off.