Paul Wilson (Compound Technologies) signed up with synthetic@pipeline.com,
which is a genuine, deliverable EarthLink address (pipeline.com MX ->
earthlink-vadesecure.net; he confirmed receipt by phone). Our code had
hardcoded pipeline.com + the synthetic@ prefix as a 'non-deliverable
FMCSA-census placeholder' and silently suppressed every automated email to
him (checkout provisioning, order-creation validation, intake reminders,
set-password invites). Nothing in the codebase actually generates that
address, so the placeholder rationale was wrong. Removed pipeline.com and the
synthetic@ rule from all four suppression sites; only RFC-reserved
example.com/test.com/invalid remain blocked.