The entire country pointing and saying "You people are crazy and dangerous" is a better safeguard than throwing some folks in jail. (Hitler got thrown in jail too, and look what happened to him...)

From Hatewatch, yesterday: Legal problems for neo-Nazi Bill White keep piling up. Already in jail for one crime and awaiting sentencing for another, the 36-year-old racist was just indicted in Florida on six counts of using the Internet to make violent threats against investigators and a judge. [...] Count 1 of the indictment accuses White of sending a May 19, 2012, e-mail that "contained a threat to kidnap and injure" the three named officials and "specifically to kidnap, torture, rape and kill those persons and their spouses, children and grandchildren."

Did you forget to tell him he was "crazy and dangerous" or something?

Maybe not. According to this week's Private Eye John Terry got one against "persons unknown" last year, but it was quashed by Justice Tugendhat because by not mentioning any specific targets, the lawyers were attempted to avoid a) having to tell anyone they were super-injuncted and b) having anyone argue against it.

There's also the case of Colin Montgomery, who had a super-injuction, but his identity was revealed by a newspaper which hadn't been told about the injunction.