Not sure if this has been brought up before or not, but I think another addition with the ability to toggle it on or off or dependent on game difficulty is make it where some of the people who look like any other citizen of Bolivia support the cartel and will radio your position to them if spotted. Responses could be an ambush/road blocks set up on the road which you are traveling or a group of 10-20 respond to the area you were noticed and conduct a search for you, maybe a combination of both. They could respond in ground, air, or even sea vehicles if appropriate for the region you are in or on foot from a nearby compound. You could even make it where their ghosts could eliminate or capture the informant, but make it where if other people see the informant being taken away or killed it could lead to someone else becoming an informant due to a perceived act of injustice or even the entire populace of the town/village becoming hostile towards you.