I really don't know. I wouldn't be surprised that, on the entire planet, a niche market could exist that would want to pay the premium over say, giving an envelope to a notary.
You could also change the business model to allow NOT decrypting messages by paying the message author (and take a commission) but I guess that would attract more than shady customers :)
You could also change the business model to allow NOT decrypting messages by paying the message author (and take a commission) but I guess that would attract more than shady customers :)