The MESSI (Managing Ethical Studies on Sensitive Issues) study used hypothetical scenarios, presented via a brief online survey, to explore whether payment amounts influenced Australian children and young people to participate in social research of different sensitivity. They were more likely to participate in the lower sensitivity study than in the higher at all payment levels (A$200 prize draw, no payment, $30, or $100). Offering payments to children and young people increased the likelihood that they would agree to participate in the studies and, in general, the higher the payments, the higher the likelihood of their participating. No evidence of undue influence was detected: payments can be used to increase the participation of children and young people in research without concerns of undue influence on their behavior in the face of relatively risky research. When considering the level of payment, however, the overriding consideration should be the level of risk to the children and young people.