> Email providers must not reject valid messages. They can put them in a spam folder if they like, but they can't reject them. This is not feasible. Imagine th

> Email providers must not reject valid messages. They can put them in a spam folder if they like, but they can't reject them. This is not feasible. Imagine that a single IP is sending a continuous flood of messages which are clearly spam, as fast as possible, to a large mail provider. Requiring that mail provider to store every single one of those messages, and to not take any steps to mitigate an instance of obvious abuse, would be completely unreasonable.