Random samples have been used to link social support to a diversity of positive outcomes. When viewed within an interaction system, however, social support appears within a context of contention and disserves some while serving others. The manner in which social support is generated can both induce and suppress outcome inequalities. This is shown in the effects of fan support on team performance in major league sports. For the sports most dependent on partisan local publics, fan support functions to suppress the performance inequalities that leagues build into competition. For the sports that have cultivated expectation-driven national publics, fan support functions to induce performance inequalities that leagues seek to eliminate from competition. A computer simulation reveals that the entire amount of actual performance inequality in national public-oriented NFL football can be explained by this perverse effect of supportive publics. Perverse effects, it is argued, are essential to the functioning of interaction systems.