I always use a cover and I've never been met with opposition!!! In fact I feel as though when I'm nursing I get an uncomfortable amount of "oohs and awws " and "let me make you as comfortable as possible".. it's actually kind of awkward for me because I'm such a private person, looking for the most secret place within a few steps, the back corner Booth, or a quiet room to nurse in... unless it's family. I nursed in the swimming pool the other day, it was all girls except my young nephews and I used a cover!
I have seen one example though of a lady who really did take it too far. Walking around with one boob pulled out exclaiming that she was about to feed her baby, but never fed her baby, kept walking around shopping with her shirt and bra pulled down and one boob just dangling, it was odd to me but I just looked away and went on about my business... sometimes I do feel she could be the reason people feel breast feeding is taboo!! One bad apple spoils the lot so to speak! (PLEASE don't hate me for saying that, I'm a HUGE breast feeding advocate, and think it's one of the most beautiful things ever, and have seen countless women nurse, this is just an example I've seen personally that I can see... and again she wasn't breast feeding, she was just walking around with one boob out exclaiming she needed to feed her baby)