Actually they got the law exactly wrong. "If the police demand that you give them the key to a lockbox that happens to contain incriminating evidence" you don't have to turn the key over without a warrant. The police have to have good knowledge that the incriminating evidence in the lockbox. And passwords are just a key. This has already gone through the courts, the courts can impel you to turn over your password, if they have evidence to suggest your computer has incriminating evidence. This won't be any different, they can't take your fingerprint or dna without probable cause. I don't see how it is any different.
When the 5th amendment applies, it protects you even when the police have a warrant. Courts have not reached agreement about whether turning over a password is like turning over a key or scanning your thumbprint. See: http://www.techdirt.com/articles/20130425/08171522834/judge-...
Probably cause isn't hard to manufacture, though. I believe there was a court decision recently that said that a state's drug sniffing dogs still provided valid probably cause even though they would bark whenever their owner wanted them to bark.
