Because the Fourth Amendment protects people from warantless searches and seizures and promises privacy in our homes and effects. You say you are familiar with the Fourth Amendment. What does it mean to you?
If the cops have good cause, they can apply for a warrant. The only reason they would want to sidestep the warrant clause is if they do not have good cause. It sounds like yo
You're very pro-police which is fine, but I live in CA where the cops are most definitely not on the straight and narrow. If you don't believe me, check out the various lawsuits that are pending in the United States District Court, NOrthern District of California, where cops are being sued for stealing things from people under the guise of serving search warrants. If they are stealing from people and getting away with it, what makes you think they won't use this GPS thing for personal gain?
This will probaby have more far-reaching implications. Right now, at least in CA, a cop can grab an arrestees cell phone and go through it, taking down all numbers and reading text messages. We,. in the criminal defense arena, are seeing that this new Supreme Court ruling could undermined this intrustion into a person's privacy as well.
The US Supreme Court got it right. As far as I'm concerned, it's none of Uncle Sam's business where I've been, or how long I stayed there. I have nothing to hide, but do value my privacy! What I do and where I go is none of their business!