The police do not need a warrant to search suspects incident to their arrest. Contrary to message board expectations, it is for that reason among many others that the police will not arbitrarily place you under arrest; arrest is a big deal. If the police arrest you unlawfully and discover key evidence of a major crime, your showing in court that the arrest was unlawful can undo their case.

Seems like you could get one cop on the inside and get a get out of jail free card--murder someone, have him search your house without a warrant, find tainted evidence, suddenly you are immune from prosecution.

Usually you're not immune from prosecution; they just suppress the evidence collected in that search so that it cannot be used against you (this is a simplification; there are a number of reasons why this evidence can be used against you anyway, generally amounting to `they would have another legal way of discovering the same fact about the crime').

A salient difference in that example was that the owner was arrested and the device confiscated in the process - the activity happened on a device already in police custody. In the example in this article, there was no arrest until the phone was examined.

Police lie to suspects all the time to trick them into confessions. I don't see how that's any different.

I'd really like to see this process banned. Just because it's legal doesn't mean it's proper or just.

Wait, it is unjust to trick a criminal into revealing himself?

That's not what I said. I said that police should be able to do their work without resorting to lies and deception.

Also, notice that GP said "suspect", you said "criminal". Huge difference.

They manifestly cannot do their work without resorting to deception. Virtually all policework above the level of street patrols turns in one way or another on some flavor of deception.

The counter example that comes to mind is a detective who gathers physical evidence in order to convict a criminal. Where is the deception there?

Does this mean you're also against undercover agents and informants? What about things like bait cars?

Bait cars, drug stings, and the like always seemed way too close to entrapment for my liking.

Agreed on second argument.

How is that not considered entrapment?

Because that's not at all what entrapment is. http://en.wikipedia.org/wiki/Entrapment