> you are supposed to still continue if you strictly follow the standard
Which standard? RFC 3207 (for STARTTLS over SMTP), 2002, says: "If the client receives the 454 response [TLS not available], the client must decide whether or not to continue the SMTP session".
Which standard? RFC 3207 (for STARTTLS over SMTP), 2002, says: "If the client receives the 454 response [TLS not available], the client must decide whether or not to continue the SMTP session".