So in the article situation, the guy is a protestor and presumably suspects he’s going to be targeted by the police for it. He’d keep that stuff isolated from his usual activity. There’d be no need to generate convincing fake activity.
Certainly more of a hassle than having a PIN that can destroy everything.
Burner phone / clean phone for border crossings seems the more accessible option.
As others have noted, this is standard policy amongst many organisations, some on account of US policies and practices, some on account of other states.