Continuing the PvP theme started by the discussion of keeps, the Elder Scrolls Online team has taken a bevy of fan questions related to the topic and answered them in the latest "Ask Us Anything" series.
When a keep is under attack, is the defending alliance informed of the assault? If so, who receives alerts? Can we receive them while we’re outside of Cyrodiil and see battles on the map? Do you have a plan to deal with spying?
When a keep is under attack, everyone in the zone will see an icon on the map that indicates the assault status, so you’ll be able to easily determine which keeps are in danger. Some events are broadcast across the entire game; for instance, you’ll see a message when an emperor is crowned or an Elder Scroll is captured no matter where you are. As far as spying goes, there are only so many systems we can put in place to prevent it before we end up getting in the way of fun, so we need to be cautious. We can, for example, prevent players from joining a campaign if they have a character of an opposing alliance assigned to that campaign.
Read all the questions and answers on the Elder Scrolls Online page.