Technically it is viable, but realistically it will result in nobody using your service. If you talk to Facebook users, most are very wary these days about giving third parties access to their Facebook account as third parties have historically abused that access (to post things, spam their friends, etc).<p>Plus the strength of this approach is directly proportional to the level of reward. Without knowing what a person &#x27;wins&#x27; if they successfully bypass your check, it is hard to know if the check itself is strong enough.<p>It ultimately isn&#x27;t that hard to make a fake account and add three other random&#x2F;fake accounts. Takes about ten minutes. Then wait a month. The question is, is the reward worth the hassle?<p>I don&#x27;t have a better&#x2F;alternative way of doing this. Online age verification is an on-going problem, and gender verification is a pandora&#x27;s box (in particular related to LGBT issues).