Well, we take up new technology without considering where it leads us, so in a sense, I'd say we're forced to deal with these things on a case by case issue. But what issue are you talking about exactly? Everything to do with our Rights and the internet/computer technology, or more specific to this kind of case? Because if the latter, I'd say that's already the case with search warrants, so I don't see how it's all that big of a leap to make the equivalent true for computer storage / property.
Well, again, I'm not so sure the warrant thing is applicable here. They already have what they were looking for, they just need help or time to translate it. Remember, encryption isn't impenetrable. It's merely time consuming.
And something that hasn't been thrown into the mix here is that the only reason they're up shit creek is because they didn't bother to look forward during their investigation. The thing that gives people the greatest pause here is that it would set a precedent where anybody could encrypt anything and it's like a get out of jail free card. Truth is, there are tons of back doors to be exploited. If you know that what you're looking for is encrypted, you get a warrant to plant a key logger, or you install a camera to watch her log on, or you wait until she's logged on and then cold boot her laptop. There are ways of doing what they want, as long as they're used in advance, and not after you've busted them. Frankly, the detectives fucked this up, and now they're seeking her help to bail them out.
As for your question, I'm kind of interested in seeing some precedent that says that a person is secure in their thoughts. That's actually what this comes down to, IMO. I really don't see any reason to start chipping away at a persons right to remain silent. Again, since this is a very fuzzy area, I don't see it as strictly the provision of evidence. I see it as equally pertinent to providing self incriminating testimony. The two seem inseparable in this instance.
BTW, there actually is a precedent for your point of view in this. Some dumbass let a border guard see some naughty pictures on his laptop coming back from Canada. Before they could copy and log the evidence, his laptop went into sleep mode and encrypted itself. He naturally told them he had forgotten the key. A judge ruled that in this case, that evidence was in there was a foregone conclusion, and therefore self incrimination was no longer a consideration. Simply put, he can't incriminate himself by providing what they already know. That seems to be the basis of the judges decision here. The problem is that it's not a foregone conclusion that anything on this woman's laptop will be evidence to nail her. Since they don't really know exactly what the contents are, they can't just assume them it to be non-incriminating.