This is an excellent little story, told in an excellent way by Ken over at Popehat.
You will enjoy it.
The whole probable cause thing really does come down to two elements:
1. A specific crime has been committed.
2. A specific identifiable person and location to be searched can be named.
You can't search a specific person / location in hopes of finding evidence of SOME crime. And you can't just search any old person you want just because a specific crime has been committed. You need both elements.
The whole things makes me think of the part near the end of LOTR:
...as they came to the east end of the village they met a barrier with a large board saying NO ROAD; and behind it stood a large band of Shirriffs with staves in their hands and feathers in their caps, looking both important and rather scared.
"What's all this?" said Frodo, feeling inclined to laugh.
"This is what it is, Mr. Baggins," said the leader of the Shirriffs, a two-feather hobbit: "You're arrested for Gate-breaking, and Tearing up of Rules, and Assaulting Gate-keepers, and Trespassing, and Sleeping in Shire-buildings without Leave, and Bribing Guards with Food."
And what else?" said Frodo.
"That'll do to go on with," said the Shirriff-leader.
"I can add some more, if you'd like it," said Sam. "Calling your Chief Names, Wishing to punch his Pimply Face, and Thinking you Shirriffs look a lot of Tom-fools".
In this case, as Ken at Popehat puts it:
When the police arrest someone, or search something, the relevant question isn’t whether they can, post hoc, gather evidence to show that there was probable cause. The question is whether the search or arrest was supported by probable cause at the time. Saying “well, we asked for a search warrant and got it, but we haven’t found new evidence since, so we’re not going to try to defend the warrant” is a non-sequitur. In addition, it’s an about-face. Renton’s minions previously claimed that the internet cartoons were self-evidently illegal cyberstalking. So what more evidence did they need to gather to support that proposition — unless the proposition was nonsense from the onset?
Owie. That's going to leave a mark. Of course, Ken may be a cyberstalker himself. With laws that vague, all you need to do is annoy the prosecutor and....Wait, there's someone at the door. You have a warrant for what? For cyberstalking? AAAIEEEE!