The Columbus Dispatch recently posted an article describing a couple of defendant who were caught by the warrantless use of GPS devices.
The two men have cases in both Franklin and Fairfield Counties involving a string of home-invasion robberies. According to the Dispatch, a deputy placed the device on a car registered to one of the defendants after they were linked by investigators to the crimes. The car's movements were monitored until it was linked to another crime, and then used to track the defendants to an apartment.
The prosecutor in one of the cases summarized the government position is easy to understand terms:
If the sheriff's office had sufficient manpower, it could follow a car 24/7 without a warrant. . . . In essence, you're doing with a GPS device what you could do with officers if not for manpower issues.
One Ohio Court has already ruled that the GPS devices can be used without a warrant. That case involved tracking over a limited period of time related to a specific allegation of criminal conduct. This case, which involves monitoring over an extended period of time, presents a different situation, however. My thoughts can be found here and in an upcoming law review article here.