Should the good end of convicting criminals justify deception during interrogation? Custodial interrogation and accompanying confessions are considered a practical necessity for convicting the most serious sorts of criminals-murderers, rapists, and child molesters.

But in the Cayward case above, where the cops falsified evidence, the Florida court saw it as an offense to "our traditional notions of due process of law." The court was evidently alarmed by the unfairness of a system that allows police to "knowingly fabricate tangible documentation or physical evidence against an individual." The court feared that such manufactured documents would contaminate the entire criminal justice system. "A report falsified for interrogation purposes might well be retained and filed in police paperwork. Such reports have the potential of finding their way into the courtroom." The court also worried that if the use of fake evidence was allowed during interrogation, police might be tempted to falsify all sorts of official documents "including warrants, orders, and judgements."

A similar question could be raised about police lying. When police are permitted to lie in the interrogation context, will they refrain from lying to judges when applying for warrants? Will they feel inclined to lie in the courtroom?