Right now, the police don't even need a warrant, merely the coöperation of the corporation.
I can't remember where I read, or heard this. However, it made sense to me.
Almost certainly Sukarno (Indonesia), though that nominally had Communist concerns as well. Indonesia was a source of oil, natural gas, tin, copper, gold, natural rubber, and tropical hardwoods.
https://en.m.wikipedia.org/wiki/CIA_activities_in_Guatemala#...
https://en.m.wikipedia.org/wiki/1953_Iranian_coup_d%27état
https://en.m.wikipedia.org/wiki/Bay_of_Pigs_Invasion
Noam Chomsky should be a good source for more such information.
Just a flat-out denial of a seemingly-true statement does nothing to advance the conversation.
(Why do I call it a seemingly-true statement? Because if a local ISP, say, will answer questions from the police, without a warrant, then the police are likely to feel free to call the ISP and ask questions when they don't have a warrant. Human nature likes not having to do the extra work.)
I am questioning the claim that law enforcement doesn't need a warrant to legally view data about an individual or individuals collected by a 3rd party.
However, those cases addressed specific questions (placing a GPS tracking device, and searching a cellphone that was found upon arrest) and did not rule on the general use of the 3rd-party doctrine. I hope those cases are a sign of change in the court that will lead to broader rulings in the future, but that hasn't happened yet.
[1] https://en.wikipedia.org/wiki/Riley_v._California#Opinion_of...
Second, yes, law enforcement needs a warrant to legally compel a company to provide them with information. But what if the company (or an individual within it) is willing to provide data without being served with a warrant? Unless taking the information is in violation of privacy laws, what's to keep a police officer from using that? (Call it an "informant" if you wish to equate it with similar non-electronic situations.)
As for a company providing information without a warrant, recent case law is closing/has closed the door on a company's ability to do such a thing (not that they are, considering how many companies have stringent privacy agreements with their users).
1. If a company (or an individual) provide information to law enforcement on request, without a warrant, is that disclosure itself breaking the law? (Ignoring company policy and privacy statements here.)
2. If so, will the company be prosecuted for doing so?
3. Will the information be usable in court?
When you say "recent case law is closing the door on a company's ability to do such a thing", it sounds like you're talking about #3 (but feel free to clarify if I'm wrong). But #1 is still a concern, because it can show the police where to try to do parallel construction.