As far as I am aware the ability of super enhanced mode S will allow ATC to "see" selectively call signs inputted in the FMC, MCP mode selections etc. Clever stuff, but not yet officially implemented. A lot of airlines are stipulating that crews input the callsign into the FMC as eventually these will replace the old four digit transponder codes. As for the remark in this particular FMC you have to understand that it appears to the crew on the progress page as:"-------- PROGRESS" so it used to be funny to input something witty before "PROGRESS" I used to like "NOT MUCH" PROGRESS. You're limited to eight characters! I'm sure this crew weren't aware this was being monitored and surely didn't mean to offend anyone!