Could "Guess Pass" stand for "Guess Password?"
Under the theory that all those dirty birds listed in the Q post that used "private email" and come to find out JC did indeed use g-mail. And the practice of creating drafts/not sending then the recipient logs in to the account and reads the draft.
Everybody in the network would have to know and share the password to log on and read email drfts, right?
Is there something known as a "guest password" that would be used and shared for that purpose?
Just a random thought from a non-computer savvy fella.
If that's not it, then I'm totally lost on the meaning of "guest pass."
Bagster