I'm curious to know what tone you read into my question. I just read it again, and it reads like a legitimate question to me. Is there an authority which allows CBP to ban talking on a cell phone while they keep you waiting?

Based on what I've seen so far, I'm not convinced there is a legitimate authority that allows them to do this. I would point out that I'm talking about the time spent waiting in line. I can accept that once you reach the agent the phone should be off, however I have some difficulty with the notion that we (CBP) can keep you waiting for us, but you can't keep us waiting for you. But that's just me thinking that I'm just as important as they are.