As was proposed in the forums, here is the addition of a tech to counter espionage: when researched, it increases the cost that other players have to pay to bribe your units. I've then reduced the initial cost of spies to 600 metal (as proposed by elexis), and it is increased by 50% when this tech (reaching the current 900 metal).
Pending questions in the patch
- i've made it researchable in the market (as espionage, superseding it), but could be better to have this new one elsewhere (in the civil center) with a requirement on Espionage?
- this new tech (counter espionage) needs a clever description sentence
- there is a conflict with D173, so if this approach is kept, we should change D173 to a more versatile version which allow for such multiplier