This case happened precisely because the officers noticed the phone flash and reboot when they entered the pin. IIRC they didn't make a fuss over it, but time l

This case happened precisely because the officers noticed the phone flash and reboot when they entered the pin. IIRC they didn't make a fuss over it, but time later he got charged over the event. So whatever a duress pin does, it has to be subtle enough that anyone looking doesn't link it to the act of entering the pin.