Being spotted
Rival leaders only know what they have seen. Use that.
You can see the whole map, but rival leaders cannot. They only know about forces that come near their bases and groups, enter their land or their allies' land, or fight them.
An eye on your group's marker means a rival knows where it is, and the group's panel lists who is watching.
Military allies tell each other what they see, so a country far away may know about your group through its ally. Every rival knows where your starting base is from the news, but not what is in it.
Big forces are noticed from further away than small ones. Staying out of sight and striking by surprise really works.