It would be helpful to many of your customers if you could build in a feature into your newsletter editor that would highlight blacklisted sites before we attempt to publish. This would give us a heads up so we can delete them, thus avoiding any pauses in our ability to send. We have no way of knowing what's a blacklisted site. The threat of having our accounts paused or suspended for unknowingly using a blacklisted site is a huge factor in our decision to consider using a different provider.