Checkpoints

Don’t volunteer into a checkpoint.
U.S. Supreme Court US v. Ortiz 422 US 891 at page 896: “A search, even of an automobile, is a substantial invasion of privacy. To protect that privacy from official arbitrariness, the court always has regarded probable cause as the minimum requirement for a lawful search. … [we hold] at traffic checkpoints removed from the border… [page 897] officers may not search private vehicles without consent or probable cause.”
U.S. Supreme Court in US v Martinez-Fuerte 428 US 543
at page 556: “It is agreed that checkpoint stops are “seizures” within the meaning of the Fourth Amendment.”
at page 559: “Routine checkpoint stops do not intrude similarly on the motoring public ” if they have a way around the checkpoint.
At Page 571: “checkpoints … detain thousands of motorists, a dragnet-like procedure offensive to the sensibilities of free citizens”
US Supreme Court Aptheker v. Secretary of State, 378 U.S. 500 (1964):
“Free movement by the citizen is of course as dangerous to a tyrant as free expression of ideas or the right of assembly and it is therefore controlled in most countries in the interests of security. … That is why the ticketing of people and the use of identification papers are routine matters under totalitarian regimes, yet abhorrent in the United States.”
U.S. Supreme Court case City of Indianapolis v. Edmond 531 US 32 (2000)
“Because the checkpoint program’s primary purpose is indistinguishable from the general interest in crime control, the checkpoints violate the Fourth Amendment.”
US v. Bowman, 496 F3d 685 (2007)
Where, however, “the `primary purpose’ of a roadblock is general crime control” or the “`interdiction of illegal narcotics'”—as in Edmond—”it is unconstitutional.” Id. at 979 (quoting The Supreme Court’s Indianapolis v. Edmond, 531 U.S. 32).
If you are told at a checkpoint that they have a “search warrant” don’t be fooled. Ask to see it. An administrative “search warrant” is not mandatory. It is not a judicial search warrant.
US vs. Minker, 350 US 179 at page 187 explains that an administrative subpoena cannot coerce testimony.
“is a power capable of oppressive use, especially when it may be indiscriminately delegated and the subpoena is not returnable before a judicial officer. . . . True, there can be no penalty incurred for contempt before there is a judicial order of enforcement. But the subpoena is in form an official command, and even though improvidently issued it has some coercive tendency, either because of ignorance of their rights on the part of those whom it purports to command or their natural respect for what appears to be an official command, or because of their reluctance to test the subpoena’s validity by litigation.” Cudahy Packing Co., Ltd. v. Holland, 315 U.S. 357, 363 -364.
The right to protest government snooping is well established.

US Supreme Court, Laird v. Tatum, 408 US 1, page 28:

“This case involves a cancer in our body politic. It is a measure of the disease which afflicts us. … Those who already walk submissively will say there is no cause for alarm. But submissiveness is not our heritage. The First Amendment was designed to allow rebellion to remain as our heritage. The Constitution was designed to keep the government off the backs of the people. … The Bill of Rights was designed to keep agents of government and official eavesdroppers away from assemblies of people. The aim was to allow men to be free and independent and to assert their rights against government. … When an intelligence officer looks over every nonconformist’s shoulder… the America once extolled as the voice of liberty heard around the world no longer is cast in the image which Jefferson and Madison designed, but more in the Russian image …”