I saw a true crime show about a murder is Spokane. The police had a suspect and put a GPS device on his vehicle. Then they baited him to revisit the secret burial site by saying something like “Unless you buried that body 6 feet down, we’ll eventually find it. Animals will dig it up.” Sure enough, he went the the burial site. Police saw that he visited a remote location by tracking him by GPS. The police went there and found the grave. The GPS data was used as evidence.
With a warrent that is fine, without one is reason people complain.