Originally Posted by
garykung
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.
Another case where rules don't play well with modern technology- I mean I can send texts from my watch, and it would be problematic as heck to now say you can't look at or touch your watch while in the sterile area.