I always just take the 10 spy increase from my ally.
Sounds like the game is trolling your alliance!I've seen that event happen in multiplayer on my ally even without me building a spy network on them
Totally trivial in SP.
In multiplayer the tipoff that your ally is building a spy network on you can be... handy.
That event happens a lot if you have high professionalism.It seems even more pointless now that the get 75 spy network for free on a neighbour with lower prefessionalism event is in the game.