I'm not so sure that's true. I'm pretty sure that not allowing the police to search your house (given that they have a search warrant) is at the very least con

I'm not so sure that's true. I'm pretty sure that not allowing the police to search your house (given that they have a search warrant) is at the very least considered obstruction of justice (in the US). The difference is in the consequences of refusal. For a home search, it's usually in your best interest to open the door because it's really easy for the police to break it down. For an encrypted hard drive, it's nearly impossible to retrieve the data if you refuse to decrypt it.