I'm a vendor that just started on Alphabay and even though I have uploaded my pgp key, all of the shipping info from customers are in plain text. Even if the customer doesn't encrypt it, Alphabay should. And to add on top of that, the shipping info stays around with the order summary. Completed, cancelled, en route, etc, all orders still have personal information in plain text.
Too much risk of LE, either the site getting taken over or already being run by them. I'm out. Even if it doesn't endanger me much, I don't like putting my customers at risk and losing potential future revenue.
Entrusting the server to encrypt your data is not safe. Encrypt before it leaves your local network or risk interception.