I used to commute and knitting on the commute (with the headphones in) was an excellent way to get the seat to myself. People tended not to sit next to me but they didn't give me a wide berth either. I didn't tend to get stared at, only occasionally and generally I'd see the starer with their own craft project at a later date so I always figured they were admiring/curious about the wool and debating whether it would be rude to interrupt me to ask about it.

Outside commuting times small children are generally the big starers and want to touch the knitting...Though train guards often used to start conversations with me about cross-stich when I did that on the train...