Funny...but if I comment "nice sunset" to the other pilot and something goes wrong the media and Fed's would nail me to the wall for breaking sterile cockpit and being unprofessional. But they can run a daycare center in the JFK tower and have a 7 year-old issue clearances???
What happens if there is a runway incursion? What happens when a foreign pilot who already BARELY speaks English misunderstands the speaking of a 2nd grader telling him what to do with his 400 ton $250 million aircraft? What about that pilot in Russia who let his son into the cockpit and they ended up crashing with a child in the pilots seat. How is this different?
A mistake on either end of the radio can lead to tragedy...why would we or should we voluntarily lower the safety margin? Because it's cute??? You gotta be kidding me. As pilots & controllers we spend our careers trying to mitigate risk. While not intentional or malicious why voluntarily introduce it? I'm not sure if you noticed, but the aviation system hasn't been getting a whole lot of positive press these days. This is not what we need right now....