If this is indeed true, it is yet another piece of evidence in the case for prison reform. Prisoners are universally bored, yet in many cases insufficiently protected from one another. Read accounts of any long-time convict's time in prison and you'll hear about excruciating boredom punctuated by acts of outrageous sadism.
So I'd ask: What prevents us from using house arrest as an alternative to imprisonment more often? How can those problems be addressed? Can we "build a better house arrest" -- maybe even from within the private sector?