This started with Utah vs Streiff, Salt Lake City Police conducting surveilance of a local house after an anonymous tip. A narcotics detective watched people coming and going for short periods of time, based on his experience a sign of drug activity. This detective did not see when Edward Streiff entered the house so he could not determine if Sreiffs stay was short enough to arouse suspicions for drug activity. Detective followed Streiff to a 7-11 parking lot stopped and asked about his visit to house, during this stop Detective relayed information to dispatch, a routine practice and learned Streiff had outstanding traffic warrant, he then arrested Streiff and searched his person finding small amount of meth, Streiff was arrested and charged and convicted of unlawful possession. Generally speaking evidence found during unlawful searches is supposed to be thrown out of court under fourth amendments exclusionary rule. Rules rationale straightforward: if cops and prosecutors can still benefit fromunlawful searches what motivatio would there be to not perform them ? You can find balance of arguments easily Utah vs Streiff