Purpose: Companies are discovering the power of crowdsourcing as a source of new ideas for products and services. It is assumed that the personal engagement and the continuous involvement with a company’s products or services over a period of several weeks positively affect participants’ loyalty intentions toward the host companies. The research leads the authors to challenge this assumption. In addition to mere participation in crowdsourcing initiatives, the authors argue that perceptions of fairness will explain changes in customer relationship-related consequences such as loyalty, perceived innovativeness and product interest. The paper aims to discuss these issues. Design/methodology/approach: The authors analyzed a real-life crowdsourcing contest launched by a leading lighting manufacturer and investigated the impact of two fairness dimensions (distributive and procedural) on participants’ future behavioral and attitudinal intentions (n=121). The analysis was performed with SEM. Findings: The results suggest that fairness perceptions are significantly related to evoked product interest, perceived innovativeness and loyalty intentions. The analysis reveals that the influence of the fairness dimensions is asymmetric: while distributive fairness can be considered as a basic factor that must be fulfilled in order to avoid negative behavioral consequences, procedural fairness instead is an excitement factor that causes truly positive behavioral consequences. Research limitations/implications: The results are particularly relevant for companies launching a crowdsourcing competition under their own brand name, and for broadcasting platforms. For companies with no relations to end-users, these findings may not be as relevant. Practical implications: Organizers of crowdsourcing contests should be aware that such initiatives can be a double-edged sword. Fair Play is a must to gain the positive effects from crowdsourcing initiatives for both new product development and the customer relationship. For companies lacking the capabilities to manage crowdsourcing initiatives professionally it is advisable to rely on intermediary broadcasting platforms. Originality/value: The research is the first to investigate systematically the consequences of fairness perceptions in a real-life crowdsourcing idea contest. The authors demonstrate the asymmetric nature of fairness perceptions on three different outcome variables that are important for the customer relationship.