Stupid move on sony's part, really. Admittedly, the hacker probably shouldn't have attributed it to himself, not the best idea on his part, but arresting one person is only going to encourage someone else to keep on updating the, for lack of a better term, jailbreak software. Since the vulnerability is in the hardware, there's nothing sony can do to stop people from running whatever they want on their systems, no matter how many times they change the encryption key. (Not that it matters though, theres nothing stopping people from simply not getting system updates.)
I really don't see why sony cares. Its certainly not going to affect sales that one in maybe a few thousand of their customers could go through a bit of trouble to run a few pirated games. Sure, that one in a thousand may play a thousand pirated games in a year, but thats still only at most a few dozen lost sales each. The 360 has been cracked for years, does anyone see microsoft whining about it? They just aren't losing anything significant and they are even gaining an (admittedly very small) userbase who likes to mod games or do whatever else they want with their console.
You'd think the console companies would just take the hint that theres no benefit to having a closed platform. Those that want to exploit an open system are few and far between, and will do it on a closed system anyway. Those that don't exploit it certainly wont be hurt by it.
One could take the "it causes hackers" argument, but you only need to look at pc games to see that its hardly an issue. Sure, you'll run into a hacker once in a great while, but it's *extremely* rare. Myself, I've seen a total of 3 hackers in more than a dozen years playing pc games. Occasional good luck combined with the occasional good player and existence of those that actually do hack has created this idea that anyone who is better than you must be cheating.
Guess I'll rack this one up as another blatant publicity stunt on sony's part...