It's terrible for end users, bit to be fair here a domain that sends little mail suddenly sending a lot looks like spam. Ciscos sender base for example graphs l

It's terrible for end users, bit to be fair here a domain that sends little mail suddenly sending a lot looks like spam. Ciscos sender base for example graphs long term volume per domain as a key indicator, and their data feeds into several mail services. You're much more likely to at least get the email this way.