I don't know why they bother! I tend to seek them out to snooze on my long commute to work. But people don't notice they are in them, they simply get on the carriage that stops in front of them, and I've just been in a Quiet Zone carriage empty but for three Revenue Protection Officers talking very loudly. I moved, and one of them having clarified I was moving because I wanted peace, said, "I wouldn't get upset about it" - well, if it wasn't flagged as a Quiet Zone I wouldn't care. So why bother having them?!