1) A clan admin can specify other tags as DNH. This is a private, one-way action intended to prevent accidental hits. Your own tag is automatically included in the DNH list.

2) Clan admins can restrict attacks and harmful spy ops made by their members at the country level. The default option is "probation". All options:
a) Probation: Can only attack or harmful op NPC countries
b) Trusted: Can only attack or harmful op countries not in DNH tags
c) Unrestricted: Can attack or harmful op any country

Would definitely be more annoying to manage with 16 countries per player, but is there any interest in this?