> ...I'm arguing the US constitution doesn't offer such protection.
Luckily, the courts disagree with you, and have for -probably- longer than you've been alive. From printed page 31 of [0], discussion of the Constutionality of putting a radio transmitter in cargo in someone's car and tracking it:
But the defendant in that case raised concerns that “the result of the [Court’s] holding sought by the government would be that ‘twenty-four hour surveillance of any citizen of this country will be possible, without judicial knowledge or supervision.’” Id. at 283 (citing Br. For Resp., at 9). The Court addressed the defendant’s concern:
But the fact is that the “reality hardly suggests abuse[;]” if such dragnet type law enforcement practices as respondent envisions should eventually occur, there will be time enough then to determine whether different constitutional principles may be applicable. Insofar as respondent’s complaint appears to be simply that scientific devices such as the beeper enabled the police to be more effective in detecting crime, it simply has no constitutional foundation. We have never equated police efficiency with unconstitutionality, and we decline to do so now.
Id. at 283–84 (cleaned up).
More than 40 years have passed since the Supreme Court’s decision in Knotts, and this Court is now faced with technology that appears to be approaching the dragnet type law enforcement practice Mr. Knotts warned of. Therefore, lower courts need to reexamine the result in Knotts as technology advances past the rudimentary beeper in that case. Adhering too strictly to the Supreme Court’s language in Knotts about a person’s reasonable expectation of privacy in “his movements from one place to another” risks ignoring the Fourth Amendment principles at stake.
That analysis is from the case that people are quoting when they say "You're not entitled to privacy when you're driving on public roads.", but -as you can see- what was actually said by the court there is more nuanced than that, and
very clearly says that the rules that apply to dragnet surveillance
must be reconsidered when such surveillance becomes feasible. Tragically, it seems like even many judges who cite the case don't bother to actually read it.
The whole document is well worth reading if you have a free fifteen-to-thirty minutes.
[0] <https://storage.courtlistener.com/recap/gov.uscourts.oknd.76...>