Trading - offer a blocking deal?

[skip123]

I am sometimes given this option, often when I'm negotiating for a hard to come by resource. What does it mean and how do you activate it? Thanks..

 

[Ansive]

It means it is their only resource and they do not want to give it away. You can only trade for duplicates.
If you want that resource settle a new city, become a suzerain or capture the city. Sometimes there aren't any duplicates...
In any case, it does not matter in this game like it did in Civ4 and Civ5, just ignore it. (unless you are Montezuma)

 

[oakdragon]

I wish the player had the ability to set a deal blocker. It would make AI offers so much less painful. (e.g., no, I will never trade that great work!)