What can you tell about a group of people who don't know each other yet they say the same story about one thing?

Collaborating alien zebras

Either all experienced the same thing in their life but were not acquainted with each other before or since.

Or they were all collectively influenced strongly to repeat the dissemination of hearsay.

Quantum entanglement, my favorite!

They're either late night talk show hosts or CNN.

Witnesses to an event?

The thing that happened was big for them all.