A corn farmer is considered a free rider if he chooses not to join the national interest group his fellow farmers created, yet still reaps the benefits of the tax incentives the group lobbied for and won.
The free rider problem is an economic concept of a market failure that occurs when people or individuals are benefiting from resources, goods or services that they do not pay for. In our case, the corn farmer is benefiting from the tax incentives the group lobbied for, yet he or she made zero input or effort to contribute to the groups agenda in getting tax incentives.