There is no excuse for whipping out her boob(s) in public for all to see.
Discreteness is the key. My wife nursed all 7 of our children and simply covered up when it was necessary and we were in a public place. Little baby blanket was all it took. From 1983 through 2004. Never once had a complaint, but then she never showed anything. And there were plenty of restaurants, parks, planes and other inconvenient public places.
Often baby doesn’t cooperate with the effort to cover up and tosses the cover off or refuses to nurse while covered.