San Diego is not Los Angeles.
So holds the Ninth Circuit.
Okay, so it's a bit more complicated than that. But that's essentially what the Ninth Circuit holds.
Sure, in 2007, the Ninth Circuit held that the Central District of California could validly shackle all pretrial detainees appearing before a magistrate, without any particularized showing of good cause (e.g., that the particular detainee might be a threat). But the Ninth Circuit says that holding doesn't necessarily mean that the Southern District of California can do a similar thing:
"The policy in Howard [the Ninth Circuit case involving the Central District] authorized only leg shackles, while
this policy [in the Southern District] authorizes full five point shackles. The policy in
Howard applied only at first appearances, while the policy in
the Southern District applies to a wide range of non-jury
proceedings. The policy in Howard applied only before
magistrate judges; this policy applies to proceedings before
both magistrate and district judges."
Plus, as I said, the Southern District isn't the Central District. And Judge Schroeder explains some of these differences, as well as a bit of the backstory about the relevant courtroom in Los Angeles:
"The concerns in Howard were focused on the nature and
location of the proceedings. The primary justification given
for that policy was a concern for maintaining security in a
particular courtroom, a problem peculiar to the Roybal
Courthouse in Los Angeles. Howard, 480 F.3d at 1013. We
discussed security concerns created by “the Central District’s
practice of conducting proceedings in a large courtroom on
the third floor of the Roybal Courthouse, in the presence of
multiple defendants, where the risks of conflict, violence, or
escape are heightened.” Id.
A bit of history is illuminating. The Roybal Courthouse
involved in Howard was built several decades earlier, and
was originally designed not as a stand-alone courthouse, but
as an office building with a few courtrooms. This design is
what gave rise to the security problems discussed in Howard
and was the result of a feud between the General Services
Administration and the District Court for the Central District.
After the District Court rejected a proposal to move out of
their existing courthouse and into an entirely new one,
Congress chose instead to incorporate a few additional
courtrooms into a planned office building, which became the
Roybal Courthouse. . . . The Roybal Courthouse was thus
particularly ill-suited to accommodate modern security
concerns.
In this case, the government has not demonstrated that the
courthouses in the Southern District pose similar problems
for security. The record here indicates the Marshals in the
Southern District pointed to problems arising from the
existence of three courthouses, ostensibly brought about by
the 2012 opening of a new, state-of-the-art courthouse which,
unlike Roybal, presumably was designed to accommodate
modern security concerns."
In short, San Diego has a shiny new, fancy courthouse with modern security, whereas Los Angeles has a converted office building with a madhouse on the third floor. What you can do in the latter is not necessarily what you can do in the former.