Here's the thing...
...if there was nothing "sensitive" in the crypto file, most people would probably hand the password over just for the sake of convenience (but then why use crypto in the first place?)
My crypto files don't contain kiddy porn or anything, but they do contain account information, passwords, PINs and other sensitive information on my life. There is no bloody way I am handing my password over to plod. It would mean closing every account (current, savings, mortgage etc) and then opening new ones (activity in itself that might seem "suspicious").
So, by the simple act of trying to keep one's life in order and following good practice; one is effectively rendering oneself guilty. Thank you "Labour" and your destruction of liberty.
I can understand why plod might want to see into these files during an investigation (especially into something like kiddy porn) but damning an entire nation in order to to deal with the acts of a minority is NOT the way to do it!