You misunderstood.
The difference is what Picture and Action (risk) is presented to all other Modes via NPC actions. Thus, it can be very easily done.
It's not a "live mirror" where actual (happening) Interdictions in Open were somehow to be mirrored into other modes, as this is indeed not possible nor desired.
NPC actions in Solo/Group modes would simply reflect the general condition in the respective System(s), as benchmarked by the statistical data gained from Open Play (number and frequency of Interdictions, number of Wings, strength of NPC Wings etc.).
Yeah I used to think this would be a good thing.
Problem is that everything is generated by the BGS: NPCs, USSs, mission types, mission locations, trade items in missions, everything.
And the BGS is affected only by CMDR actions.
And the BGS is affected equally by every CMDR.
So yeah - I love the idea that you can tell what is going on in other modes by NPC activity.
BUT it's not trivial to implement. It requires change to the way the core of the economic and political system works.
And it breaks the fundamental principle that all modes are equal.
I can be a snob and say that hiding in Solo is a shameful thing to do.
But whatever is done there MUST carry the same weight as Open.
It's a core principle.