NotaCriminal

Well, your response doesn't really answer OP's original question and mine won't either, but I'll take on your response as a reason why it might be nice to be able to use a phone: If it's going to take THREE OR MORE FREAKING HOURS to get through immigration and customs (can't seem to do one without the other in the U.S.), I want to contact my airline to rebook myself on another flight and to text the same to my ride home from my final destination ASAP. Not three hours later when it's too late and I'm now stuck overnight and wasted my ride's time, all because of gov't inefficiency and an inability to lighten up on the rules on occasion when it's the gov'ts own darn fault. Have fun, indeed.

If Immigration and/or Customs can't process flights efficiently, then allow the pax to use a cell phone or a smart phone web browser until X point in the line. No, I can't see using a phone when you are close to being processed on either side, but if you are 2 hours back from seeing any agent, immigration or customs, then what the heck is the problem???

So, does anyone actually know why the rule is in place? And secondarily, why does it appear to annoy at least a couple of you that people are either asking why it exists?