[quote=@duck55223]
<Snipped quote by Willy Vereb>

Sensors are not instant. Instant Communication only means two linked points are capable of contacting each other without delay.
[/quote]I think that was the least important part of my question.
We can perhaps make quantum entanglement based instant transmission common. So there's a way to get two attuned devices to make instant message transmissions.
Perhaps you may even extend this to a quantum gate system which may have strategic significance.
Remember how e always had problems with the galaxy being too big and what solution we came up with last time?
There you go.