Originally Posted by
Boggie Dog
I don't understand the harm that a cell phone presents to CBP while in line waiting for your turn.
CBP bans cellphone usage so that passengers can't contact anyone.
For example, smugglers usually work in a team. So by banning cellphone usage, the person at the front can't signal the person after.
Originally Posted by
FlyingHoustonian
With Mobile passport app you need your phone out and on do you not?
Mobile Passport app users have a designated lane away from the main lanes. Hence, signaling out those who has a legitimate need for cellphone usage.