Just a thought ...

If you listen to you mp3 collection on you headphones in an open plan office and fart - does the fart make a sound?

I am assuming not.

Also if you walk onto a bus listening to your mp3 collection really loudly .. . .

and then ask the bus driver,

"One to Shepherds bush green"

Do you really go: "ONE TO SHEPHERDS BUSH GREEN" - really loudly.

and if you fart at the same time, do you sound like a really ignorant bastard who farts and shouts?

I am assuming not.

Just a thought.