This thread is all about Economic Treaty.
Its an agreement between two parties to set up a street between both of their factions for 10% boost in gildar.
And I really hate it. It just had little to do about one event that happened last year.
I got dogpiled by six factions immediately in following turn when last turn they all asked me for a economic treaty. I was like sure why not and enjoyed the 60% bonus in gildar for one turn.
Never again.
That single event was enough to make me refuse to sign any economic treaties in the future its only today that I'm now willing to talk about it.
Disclaimer: I survived the dogpile and killed every single backstabber for their insolence. It happened few months before The Dead dlc came out.
Because I learned an rather important lesson through that dogpile, Economic treaty is junk, what you really want from it is the road connection!
Yum Yum! Roads!
So these days I only sign a economic treaty on those who I want dead fast or Allies that I care about staying alive.
But here's a bad thing.
Screenshot!

Image 1. Pardon my terrible touchpad writing on laptop in paint program.
Party A requests Party B to get a economic treaty.
Party B declines so Party A gives up and asks for a Economic Treaty from Party C.
Party C accepts.
Party A now have the road route for speedy invasion on Party B which is why Party B declined the request from Party A in first place.
And Party A might bribe Party C to war on Party B which C might accept now because there is easy road route!
AIs always do this to me because they want the invasion road to my lands.
You can't even pillage or place tariffs on the unwanted merchants traveling through your lands without your permission -,-
You cannot even destroy or place no man's land barrier around your lands if you don't want roads being built.
AIs will force a road on you and you cannot do anything about it unless you're lucky enough to get the Image 2 situation.
Image 2.
It's only way to avoid getting any unwanted roads from opposing factions like... YITHRIL! through your lands due to the how it is currently set up in the game. Party A is forced to travel to your lands slowly for the part of the way.
Image 3.
This is the ideal yet not used. 
Party A is forced to build a road around the Party B to connect to C because Party B really hates Party A.