The quote, "If you are a Clown, Be on the lookout For things in a crown," from Gertrude Chandler Warner's "The Boxcar Children Mysteries" suggests a playful warning to be observant and aware of one's surroundings, particularly in unusual or whimsical situations. It emphasizes the importance of being alert to hidden details and secrets that may be overlooked in everyday life.

This theme reflects the adventurous spirit of the book series, where the Boxcar Children often encounter mysteries to solve. The mention of a clown and a crown evokes imagery of fun and curiosity, inviting readers to engage their imagination and embrace the challenges they might face in their own lives.