Wouldn't this be easy to defeat by changing words around yourself before distributing? It would either match to someone else's copy of the email, or not match a

Wouldn't this be easy to defeat by changing words around yourself before distributing? It would either match to someone else's copy of the email, or not match anyone at all. It would need to be highly resilient to a lot of tampering, which doesn't seem reasonable for relatively short documents like emails.