The purpose of the exclusionary rule and the &quot;fruit of the poisonous tree&quot; is to prevent the police from purposely violating the 4th amendment. There is no other reason why illegally obtained evidence shouldn&#x27;t be used to convict a criminal.<p>So the good-faith exemption exists to make sure technical violations that occurred during a good faith attempt at following* the constitution don&#x27;t result in a criminal going free.<p>Think about it. If your mom gets murdered and the cops get a warrant that for some reason wasn&#x27;t technically valid, would you want the murderer to get off scott free? How that that serve justice.<p>I think the court may be misapplying the good-faith exemption. In my jurisdiction it only applies only in situations where there was a defective search warrant. But each state may be different.<p>TL;DR; it doesn&#x27;t make it legal, but it also doesn&#x27;t give you a get out of jail free card.