[troydavis]

I’ve done it and had well-known ESPs write personal responses (not templates) saying they’ve contacted the customer about the problem. They could be outright lying, but that probably wouldn’t scale well beyond a small support group.

I believe the incentives are more aligned than you might think. An ESP isn’t risking revenue by telling a customer that something’s not working and making them fix it. All parties know that ignoring it manifests in poor deliverability, often quickly (thanks, Gmail “Spam” button!). In my experience, your skepticism is justified about ESPs permanently shutting off a customer, but they’re comfortable doing anything short of that.