[mark212]

The US Supreme Court just made the distinction, when ruling that access to a cellular telephone carrier's location data for a particular subscriber required a warrant (and hence a showing of probable cause):

   The Government’s position fails to contend
   with the seismic shifts in digital technology
   that made possible the tracking of not only
   Carpenter’s location but also everyone else’s,
   not for a short period but for years and years.
   Sprint Corporation and its competitors are not
   your typical witnesses. Unlike the nosy neighbor
   who keeps an eye on comings and goings, they 
   are ever alert, and their memory is nearly
   infallible.

_Carpenter v. United States_, No. 16-402 (June 22, 2018) (Slip Op., at 15)

That's the difference, beyond simple public/private. It's not that the license plate display itself is private but storing the data forever and being nearly infallible amounts to an unreasonable intrusion on privacy when handed over to the government. Notably, the USSC in a 9-0 ruling from 2012 held that attaching a GPS tracker to a car also required a warrant. _United States v. Jones, 132 S.Ct. 945 (2012).

[gremlinsinc]

Too bad this didn't come up, when the supreme court was more liberal, now it'd surely be shot down. (applying the similar scenario to the license plates)

[jessaustin]

That was less than a month ago.

[HillaryBriss]

yep. one of the interesting things about Carpenter v. United States was that Chief Justice Roberts (a Bush appointee) joined the more liberal members of the court to form a 5-4 majority.

perhaps even more interesting, Trump appointee Gorsuch seemed to be saying that even more general data privacy could exist under the fourth amendment: ... it seems to me entirely possible a person's cell-site data could qualify as his papers or effects under existing law.

this offers a far better explanation than i can give: http://reason.com/blog/2018/06/22/scotus-rejects-warrantless...

[jessaustin]

Yeah if one actually pays attention to what Gorsuch wrote this was more like a 6-3 decision. I almost feel like he's reaching out to Thomas with this dissent, so that next time around Thomas will feel comfortable limiting police power. I think Alito is a lost cause, and now Kennedy is gone. If Gorsuch and Thomas are both down for 4A, one could imagine Roberts joining them. At that point one could imagine a 7-2 or even 8-1 decision in favor of restoring the Fourth Amendment over all state activity. That would be great, and one could trace it back to this "concurring" dissent...

[jrs95]

It's a bit naive to assume that privacy is a binary "conservative" vs "liberal" issue. Specifically applied to ICE I'm sure a "liberal" court would have been opposed to it, but both parties are very anti-privacy and the courts are so politicized now we may as well start putting Ds and Rs next to judge's names.