The legislators weighed this all out and made the shield law. You are second guessing them, which is fine, but second guessing doesn't change the actual law. It was made to protect journalism and with very good reason. And in this case it is very easy to see that the line drawn in the law may have been crossed.
My opinion, rather, has to do with the distinction between the letter of the law and the spirit of the law. The spirit of the shield law is was never to allow a journalist to commit a felony and evade discovery. Rather, its spirit was to allow a journalist to protect sources who may have committed a crime.
(And, even then, shield laws won't protect a journalist from being jailed - despite a shield law - for contempt of court. Judith Miller, a NYT reporter, was jailed for 3 months for refusing to reveal, to the government probe, the source of the leak of Valerie Plame's identity.)
Admittedly, the current case is a mixture of the two, because it's possible that the source committed one felony, and some folks at Gizmodo committed another.
I'm not saying that the search warrant should have been allowed. I was just responding to the alarmism about the hypothetical police chief run amok.
After all, the chief cannot write his own warrants. A judge must be involved, and there must be probable cause.
The definition of probable cause in the case of a search warrant is already pretty narrow: the chief would need to present the judge with information sufficient to warrant a prudent person's belief that evidence of a crime or contraband would be found in a search.