The argument made in the article is that it's a "foregone conclusion" that there's child porn on the drives, so decrypting them isn't self-incriminating because they already know what's on the drive.
That said, personally I don't buy it. What if there's evidence of other illegal acts on the drive too, ones the police don't know about? Then decrypting the drive would definitely be incriminating because it would tell police about the other illegal stuff, stuff which fails the "foregone conclusion" test.
That said, personally I don't buy it. What if there's evidence of other illegal acts on the drive too, ones the police don't know about? Then decrypting the drive would definitely be incriminating because it would tell police about the other illegal stuff, stuff which fails the "foregone conclusion" test.