Originally Posted by
mahohmei
I can think of only one reason to prohibit cell phones in Customs: the same reason they're not allowed at the counter at the Post Office. People who talk on cell phones tend to pay attention to nothing else, and they don't want anyone holding up the line, and they don't want to have to compete with your phone for attention when it's your turn.
I have never seen a line at Customs in the U.S. You get your bags, you hand in your landing card, and if they want to check what you have they do. If they are checking one person they generally let everyone else through.