The most common argument used in defense of mass surveillance is ‘If you have nothing to hide, you have nothing to fear’. Try saying that to women in the US states where abortion has suddenly become illegal. Say it to investigative journalists in authoritarian countries. Saying ‘I have nothing to hide’ means you stop caring about anyone fighting for their freedom. And one day, you might be one of them.
Just tell them unlock their phone so you can take a look of his browser history. Works quite a few time for me.
At one time I did, and to my surprise, my friend did just that! Unlocked their phone and handed it to me without a word. Welp.
"I don't trust you!" But they trust whatever NSA-agent looking at their private photos not to save anything for later..