Or offer them a Comtrex, cough drop or other something to help them .... sometimes such illness doesn't really raise its ugly head until one is on the way to the airport and then caught without....happens to be most considerate. Also, I cough due to dry air on aircraft...I always cover my mouth and I'm not emitting cold/flu germs but I am coughing...a cough drop helps and I carry them handy for during flight. Hope the person feels better and hope they realize all those lessons back in grade K were meant to last a lifetime!