That makes no sense. Why aren't the FBI in violation of CFAA, then?
Expectation of privacy defines the bounds of a search. Police searches are not permitted to conduct otherwise illegal activity Just because they are searching.
>(f) This section does not prohibit any lawfully authorized investigative, protective, or intelligence activity of a law enforcement agency of the United States, a State, or a political subdivision of a State, or of an intelligence agency of the United States.
So something can't be illegal for the police to do for the sole reason that it violates the CFAA. If it violates something else, I suppose CFAA charges can be added on, though.
The CFAA does not depend on any expectation of privacy, only authorized usage.