The US Transport Safety Administration (TSA) has let it be known that international travelers heading to the United States will need to power on their mobile devices before being permitted to board their flight. This change in the TSA screening process is due in part to apparent threat intel against airlines heading to US. Be sure to keep your mobile devices full charged if youre traveling with them. Also, be sure to remember that the TSA should not ask you to enter your PIN into your device. You only need to demonstrate that they device will power on.”]
Source: https://www.csoonline.com/article/2450487/tsa-power-up-your-mobile-or-lose-it.html