Ok, first if you committed an infraction just pay it and be done. You broke the law, now pay the consequences. If a person from a Latin American nation broke the law in Europe, you would expect them to pay the fine and/or be prosecuted to the full extent of the law. You would expect and demand nothing less than that.
However, if you have been stopped needlessly or without just cause, then it is a shake down. Refuse to pay anything. If you do you are supporting the corruption in the system.
Way too many people are way too fast in expecting a cop to be corrupt and don't even let the cop offer you just a warning, they jump all over him/her and make them nervous and angry. It is their country, you are the visitor, you made the decision to enter it and you must abide by their rules. If you are patient, courteous, and have not committed an error you will likely be rewarded with nothing more than a delay and some debate between you and the cop. Start whipping out a camera and taking pictures of the cop and filling out a false form and you are antagonizing the cop. How would you expect a cop in England to react if a rider from Central America began arguing, taking pictures of them, and filling out some false form?
In the end it is up to you to decide to become either part of the solution or part of the problem. Corruption exists because riders will pay and you are not doing any favors for the next rider passing through. Start an argument with a cop in Latin America and you better be prepared to see it through in case the cop calls your bluff instead of him calling yours. That form will make handy toilet paper in the local lock up.