[mindmachinery]

>enable whitelist/blacklist zones via geolocation

This is exactly the approach I took with my password vault application (android only, far less well-known than 1password). I added a location-lock feature that allows the user to store a number of "safe locations" outside of which the vault simply will not decrypt, even if the correct password is entered.

The app also makes it very clear that location lock is enabled and that the user is outside of all "safe zones" and therefore will not unlock. The only way a border agent is getting access is to figure out the GPS coordinate encryption method and adding a new set into the sqlite db or physically driving to one of the safe locations and unlocking it there.