I dunno, once data gets taken, whether encrypted or not, you have to mention that it's been taken. From the security articles I've read over the years, I've come to understand that if someone has stolen the data you have to assume they'll find a way to decrypt and access the data.
For instance, rainbow tables are useful to brute-force guess hashed passwords, and with the amazing computing speeds capable on desktops these days, you can actually create rainbow tables that include salt values. Especially if you stole the salt value(s) while you were in there plunderin' the databases (yarr!)
Still, it's not _that_ far-fetched to think that Sony might have employed less-than-perfect programmers who don't know to salt and hash passwords...