We have something called the third party doctrine, which stems from Supreme Court cases in the 1960s and 70s.
Basically you have “no reasonable expectation of privacy” with respect to any information that you provide to a third party who is not an attorney providing counsel or a doctor. Your bank records for example, do not require a warrant to access under this principle.
All of this put in place by the courts. Stranger still, this sort of thing has become something that “conservative” judges are champions of.
There was an article on HN recently about how Google does something like that, internally. It claimed employees CC in house lawyers to tag attorney client priviledge on emails they wouldn't want, e.g. antitrust investigators, to obtain too easily. Even if it just delays discovery or adds friction, mission accomplished.
The notion that my papers inside of my rented apartment have dramatically more protection than my data inside of a rented server is absurd.