How many like people in unison in quiet unison intoning
"Please be considerate and hang up now" over and over and over would it take I wonder?
Personallly after a few moments I would forcibly make them hang up. I'm not kidding I'd proably get arrested, I detest the damn things even on trains.
Public transport of any form can wind me up that way. Even stuck on the tube with tourists chatting in whatever foreign language ups my stress levels as it's just a noise in my personal space I cannot escape.