You would have to examine the source code outside of the PREFIX section. Many programming languages have preprocessing directives like #define which would allow you to do something like this:
#define COOPERATE DEFECT
Where the compiler would replace instances of "COOPERATE" with "DEFECT". I can think of few other ways to game this without touching the code between the PREFIX tags.
Information wants to be anthropomorphized. ~ Anonymous
Don't anthropomorphize computers. They hate that.