Here's what I think happened back in 2004, after the abduction. Bruna knew how much Sean meant to David, so she figured he would want to see his son so bad that he would give in to the demands. What she DIDN'T realize was that his love for Sean was SO strong that he sacrificed everything to try to get him back. As someone said somewhere in a previous thread, the whole clan did not expect this to drag on THIS long, and did not think they would be exposed for their underhanded manuevers.