On the other hand, if you drive your Illinois car around on the freeway in Nebraska with expired Illinois plates, you will be pulled over, and the reason I know that is guess.
Help me understand why a transponder violated the sanctity of your car, but the valid state license plate, issued by the state and required on every vehicle, so as to allow the police to identify your car from a distance despite any individual interest in privacy doesn't. You can't even see the transponders.
I don't like being singled out for special treatment without some judicial oversight. That's the problem with the GPS trackers; the sneakiness of it. If it were done out in the open, then I wouldn't mind.
A sticker or plate is placed on your car with your permission and knowledge. And when you accept it, you know that you are being treated just like all the other drivers.
A transponder is placed on your car (property) without your permission and without your knowledge. You are singled out for special treatment (tracking) by the police.
In the US, except for certain exceptions, searches require a warrant issued by a judge and probable cause. A search is an examination of another's property to look for evidences of a crime.
The biggest exception to the warrant requirement is the "plain view" exception. Police do not need a warrant if evidence of a crime can be seen in "plain view" without trespassing or employing special means to search.
So if you've failed to register your car, police can see this from plain view. They are not required to avert their eyes to not see the missing or expired tags. They don't need special equipment to see the tags. So they don't need a warrant to "search" for failure to register.
On the other hand, placing a tracking device and monitoring it is not within the plain view exception. Police must do considerably more than fail to avert their eyes in order to use the tracking device. They must have targeted a particular car for a search. They must place a transponder on the suspect's property without the suspect's permission (this is a trespass by the way). They must use special equipment to track the transponder. It is not visible or detectable with the unaided senses.
The difference between tracking a suspect with the naked eye versus using a transponder is like the difference between questioning a suspect and observing his reactions and body language versus giving the suspect a lie detection test. Police are not required to get a warrant to pay attention to how a suspect reacts to questions. But as soon as they start monitoring him with special equipment, then they have to get a warrant (or get his permission.)
Plain view is an exception to the warrant requirement, not the other way around. The rule is that police cannot search without a warrant. Plain view is an exception because it makes little sense to require police to ignore obvious signs of crime just because they don't have a warrant. After all, part of their job is investigation. But they have to do their investigation respectful of citizen's rights unless they get special, limited permission from a neutral judge.
(Edited to add the last paragraph.)
But we're not talking about search. We're talking about using technology to capture information in plain view that is explicitly made available to law enforcement.
The differences between GPS transponders and lie detector tests are numerous, including how invasive they are (having devices hooked up to your actual body), the fact that they require detaining you, and the fact that the police have absolutely no business attempting to ascertain your private thoughts, but are explicitly entitled to track your car.
(Lie detector tests are also a psychological ploy; they don't actually do anything.)
You're right and this is the key to the whole problem. The Supreme Court has ruled that the Fourth Amendment does not protect a person against a search unless the search violates a person's "reasonable expectation of privacy."
So the police can search through your garbage, phone records, or bank statements because supposedly you don't have a reasonable expectation of privacy in those things since you've abandoned/given away your garbage to the trash co, let the phone co know who you want to talk to, and allowed the bank to keep track of your money.
So, the reasoning goes, a search of those things is outside of the Fourth Amendment: it's not even a (4th Amendment) search. Even though every non-lawyer normal person knows that it is. A search is just an attempt to look for something. And people normally do expect privacy in their their garbage, phone records, and bank accounts.
So now government can use dragnet software to continually track everyone's phone calls, bank transactions, internet usage, maybe email (people allow Google to read their mail so that Google can serve up relevant ads), maybe unencrypted wifi communications. No doubt in the future government robots will comb through everyone's garbage at the dump looking for evidence of crime. Next to this, planting tracking transponders on a car doesn't seem like such a big deal.
> If you're placed under arrest for any reason, you can be searched, your person can be searched, any belongings you're holding can be searched, and your immediate vicinity (ie, the passenger compartment of your car) can be searched.
I don't think the search incident to arrest is quite that broad. The police can search you and your immediate area for weapons and evidence that may be lost or destroyed, but, for example, I don't think they could search inside a locked briefcase, sealed letter, laptop, or cell phone (see http://www.policechiefmagazine.org/magazine/index.cfm?fuseac...). They also can't search your car for evidence of a crime for which they don't have probable cause if they already have you in handcuffs in their patrol car. (http://en.wikipedia.org/wiki/Arizona_v._Gant)
> (Lie detector tests are also a psychological ploy; they don't actually do anything.)
Successful passage of a lie detector test has been enough to get prosecutors to drop rape charges in a he-said-she-said case. (I was interning at the public defender's office at the time.)
Thanks for the reply. This discussion helped me to clarify my own thinking.