So we can't carry cash, because they'll seize that directly. This device could probably do some sort of run around the new chip system in cards. Bitcoin is nearly useless in the real world. So where does that leave us? Google & Apple Pay on our phones? At least our phones can be password protected.
Carry a credit card and pay that off monthly so as not to accrue interest. This way the only thing that could potentially be "seized" is your access to a line of credit. Now, I'd normally say that there is no way they could justify seizing assets that aren't even yours, it'd at least be entertaining to see if it did happen.
After I had my debit card skimmed I started to have my debit card always deactivated by default. I usually only pay by credit card anyway. In cases where I need money from the ATM I enable my debit card via my bank's mobile app, get the money, and then disable it again.
And you'll get an obstruction of justice charge if you don't supply the password then and then be found in contempt of court if you don't give it up when you're before a judge.
Not in this case. The police legally can't pull you over and force you to unlock your phone via password. They'd have to go through a court process, and that's precisely where any attempt at theft will fall apart (more specifically, as the law stands today the police won't even attempt this line of approach because they know it'd fall apart in the court system before they're able to steal the money).