As I understand it, a judge can decide whether or not to permit reporters in the court, and can try to get reporters to agree to specific conditions. However judges can't tell reporters that they cannot tell people about a case, and cannot keep reporters who happen to hear details from reporting them.
By contrast in Canada judges may say that they don't want something reported, and nobody is allowed to report it. Period.
Furthermore my impression of how common permanent publication bans are is different from yours. Specifically I understand that it is rare for an entire case to not be reportable (excepting cases involving minors - and there are lots of those), but fairly frequently a small portion of a case is permanently banned (eg testimony from family members about how much grief they went through, which doesn't affect whether the verdict is guilty, but may affect sentencing).
Cheers,
Ben