> There is a difference if you report to the cops and if the cops come to you and ask you to report. These are completely different.

So, when the police ask the public for information related to a crime, it should be illegal? I disagree. The police shouldn't be prohibited from asking anyone for help.

> I do not think it is hard to read as "The government is not allowed to collect information on people without warrants and without due probable cause."

It might be easy to read it that way, but that doesn't make your rephrasing a correct characterization of the writers intent. The 4th has never prohibited the government from collecting public information, information volunteered by the public, anything they observe in the course of their duties, or literally anything else that isn't compelled. The government has always collected these types of information, both now and at the time that this was written. The writers were aware that police need to collect information in their own investigations, and from other people, to do their job. This is why they specifically wrote what they did, and did not write your rephrasing.

> What a person knowingly exposes to the public, even in his own home or office, is not a subject of Fourth Amendment protection. But what he seeks to preserve as private, even in an area accessible to the public, may be constitutionally protected.

Right, phone booths do not have any rights under the 4th. And if Charles Katz is in a phone booth, he expects the conversation to be as private as speaking in a phone booth is. But if Charles Katz gambling partners at the other end of the phone decided to snitch on him, that's legal for them to do, even if Charles Katz didn't want them to.

Make no mistake, Justice Potter is definitely not saying "if you tell someone about a crime, it's illegal for them to snitch". He's saying that there are situations in public spaces where privacy from direct government surveillance is expected. Phone booths, bathroom stalls, changing rooms, etc. These are public spaces with some expectations of privacy. But there's nowhere, anywhere, that other people are prohibited from talking about you to the police.

> The government (or "friend") creates a private corporation. Private corporation does everything that the government cannot do without getting a warrant. Private corporation then gives the information to gov. How is this not a loophole?

Because the government has a monopoly on the use of force. If people working for a private corporation searched or seized information from others by force, it would be a crime. Data brokers do not use force to obtain their data. There is no search or seizure happening when you volunteer your data to a data broker or their affiliates.