An ImmigrationProf blog post asks that question and says the answer might be “yes.”
The U.S. Attorney General and the Secretary of Homeland Security last week responded to Chief Justice Tani Cantil-Sakauye’s request that immigration agents not “stalk” undocumented immigrants and make arrests in California courthouses. (New York Times and Daily Journal [subscription] coverage here and here.) Among other things, their letter “encourage[d]” the Chief Justice to express her concerns to Governor Jerry Brown and “local officials who have enacted policies that occasionally necessitate ICE officers and agents to make arrests at courthouses and other public places.” One of those policies, the letter says, is “denying requests by ICE officers and agents to enter prisons and jails to make arrests.”
The ImmigrationProf Blog reports that ICE requests have included asking local jails to “detain for an extra 48 hours immigrants who have served their jail sentences and are entitled to release” (see here and here) and that a federal court has ruled such detentions to be Fourth Amendment violations.