The Border Patrol officers routinely ask people for their cell phones and passwords, and indicate that you will not be allowed to enter if you refuse. So the implementation of this proposed rule could be as simple as searching your phone for apps like Jaxx and Coinbase, and in this way they look for themselves whether you "have" cryptocurrencies as you cross the border. This way they can find out what you own outside the banking system -- which is the real purpose of this bill. They know you are not crossing the border with currency. They just want an excuse to detect your holdings. This is another basically futile attempt that can probably easily be circumvented by smart people. For example, you put all your cryptocurrencies onto paper wallets and mail them to yourself, keeping all your passphrases and account numbers in non-digital (printed out) format safe at home -- and delete any apps from your phone so there is no indication on your device that you "have" cryptocurrencies while crossing the border. I'm not saying they can never figure out a way to find out what you own. As detailed in the book, "Lucifer's Banker," Hillary Clinton protected all but 4,500 out of the 52,000 Americans who had accounts at United Bank of Switzerland (UBS). But none of us are in that elite group that can escape the Forced Disclosure rules as they become more and more refined. Grassley's attempt is just the first one.