The Court unanimously held that since the use of such a device did not violate a legitimate expectation of privacy there was no search and seizure and thus the use was allowed without a warrant.

[2] Minnesota law enforcement agents suspected that one of the defendants was purchasing chloroform for the manufacture of methamphetamine, an illegal drug, and arranged with the manufacturer to have a radio transmitting beeper placed within the drum of chloroform the next time it was purchased.

Following visual surveillance of his cabin, the authorities acquired a warrant to search the premises, and used the evidence found therein to convict Knotts.

[3] The Court ruled that a "person traveling in an automobile on public thoroughfares has no reasonable expectation of privacy in his movements from one place to another.”[4] Such information—the starting point, the stops one made, as well as the final destination—was voluntarily conveyed to anyone.

Because of the trespass, it was unnecessary to consider whether there was a violation of an expectation of privacy based on using the GPS for long term, continuous surveillance.