Seemed like they meant a refund would be given if someone discovered they had been shadow-banned and requested a refund because of that, however still if that is their policy that could be a possible lawsuit risk if someone had been paying for a platform where they think people can read what they post but it turns out that was a lie.
I agree with you that there are risks to using shadow bans, either via lawsuit or to the trustworthiness of your business.
But even without a lawsuit, the goal here was to determine whether shadow bans have any valid use case, not to demonstrate how to deceive customers to get their money. The answer to the valid-use-case question is even easier when you are talking about paying customers. You simply stop accepting their money, no shadow bans necessary.