What if you notice someone breastfeeding, but only because you see a baby-shaped lump under the shoulder blanket and see little feet sticking out -- still offensive? I.e., is it the mere knowledge that someone is discreetly breastfeeding nearby that offends you? Or is it actually seeing skin/suckling?
Your "what if" is moot, because a blanket means I don't notice.
Nipple, I notice.
Seeing skin and lips attached to it, that's offensive.