Which will all be blacklisted as will the subnets within which your IPs sit and then your hosting provider or ISP will terminate service.

I know this is kind of a disparaging comment, but I would really like to hear their response to it. There have been numerous good services similar to them in the past and all have been placed on spam listings and blocked by most major services. Mixnet solutions have worked for over 30 years, they aren't particularly novel, what is novel is having an email service that allows reasonable privacy whilst not ending up on a spam listing.

I'll do my best to prevent spam being sent by the service and therefore avoid being placed on a blacklist in the first place. I know it may be difficult to avoid landing on any blacklists but the server does currently have some reasonably strict anti-spam measures in place and I'm constantly looking for ways to reduce any spam to a bare minimum.

All forwarding addresses (recipients) on the site must be verified in order to receive forwarded emails.