What if you set a durress password to something simple like 12345, plead the 5th, and the cops try to brute force your device? Would it still be your fault or is it the cops fault since they are the ones who entered the password while trying to bypass your phone's security measures?
Also, what if you explicitly tell them there is a durress password, but refuse to tell them what it is? Surely if they were informed of the risk and proceeded regardless the blame would fall squarely on them for risking a process that might "destroy evidence"