Good luck arguing that in court, no matter how correct you are. Lawyers cost a lot of money.

Still, no one's going to sue you personally for this. However, there have been cases of legal action against those who make "hacking tools" available. I believe there was a case against Apex for their cheap DVD players that ignored region codes, for instance.

Anyway, the keyword here is "threatened". Corporate lawyers make all kinds of baseless legal threats all the time. It should be illegal.