That depends on your scale. The big email providers cannot afford to block large organizations. However a "little guy" they can ignore. The US isn't part of t

That depends on your scale. The big email providers cannot afford to block large organizations. However a "little guy" they can ignore. The US isn't part of the ICC, but there are plenty of other governments who are and take this seriously. At least one will make a big deal about the ICC being blocked and governments have more power than even large companies.