I used to knit a bit too, especially while in transit, and here's my experience :
I was used to get back home with the last tram in the city I lived but I had a correspondance and I would always see second tramway leave when my first got to the stop I was changing trams, so I'd have to wait for 20+ minutes at the stop. It was night (it was often the last one I was taking) so the whole place wasn't so reassuring.
But when I was knitting there, people (especially old ladies, but all sorts of people really) would come to talk to me about what I was making, and even when nobody was talking to me, it felt like if I had an aura of cosiness around me and people were more comfortable.
I think because knitting is so related to sweet old ladies, it makes people look inoffensive and maybe more sympathetic ?
Anyways, just to say I think it's a really good idea !