I'm late to the party.
Oh, why do I live under the rock I live under?
Here's a link to a reply Miss Manners gave to a reader who had a problem with knitters knitting when they should otherwise be paying attention.
Generally I entirely agree with Miss Manners. There's a few exceptions, but I find most of the advice she gives seems to be common sense.
Except this nugget.
I don't happen to think it's common sensical to knit in a place where you would otherwise be expected to pay attention. In a place where your apparent (apparent, to non-knitters, of course) lack of attention is read as insulting and rude.
I know I can pay attention to the world around me and knit at the same time. I know my knitting isn't loud, I'm not moving around and creating a distraction for other people.
But, a lot of living in society, dealing with other people, and operating under the banner of politeness dictates that you must take other people's feelings into account: act empathetically.
I figure most people (especially non-knitters, but knitters aw well) would read one's harmless knitting as rude.