There was one guy who went to Columbia who nearly got arrested for starting a riot. Though he was well-intentioned, he didn't anticipate the reaction when he started tossing his money to the crowd of "peasants" behind the fence, as he boarded the plane.
Something else that was striking: I was working at a food factory that was built like a prison. The building was made out of concrete, complete with high-security windows, and not many of them. There were two high fences surrounding the complex and covered with barbed wire [the military stuff]. Upon entry, one went through a guard station [complete with machine guns], and then entered the area between the fences. After the gate behind us closed, the next gate was opened which allowed us to enter the parking area. From there we passed through two more security checkpoints before entering the factory. The factory manager was our escort, so I asked him why they had all of the security for a food factory. "Where do you think the people go when they run out of food?", he replied.
Off topic but intereeting: In S. Korea, they don't put any identification on the office doors in business complexes; office managers, supervisors, vice presidents, etc. This to avoid assasination and kidnapping attempts. You have to use a proprietary map and count the doors in order to find the correct office.