Sorry for joining in on this board. I was just lurking and saw this.
I have BFed both my babies in public and to be honest i have never once received anything but smiles and positive comments. A couple of older ladies have sparked up a conversation with me about how lovely breastfeeding is and that they fed theirs that way etc. I've even had one woman congratulate me on doing it in public and say that she wishes attitudes were the same back in her day cause she always had to go and sit in the car, even when it was freezing cold!
Most people just assume that baby is sleeping and will look and go "Aw, how cute, he must be tired!" and stuff like that.
The only slightly negative i've had, which is entirely my perception (that could be totally wrong) is that twice i have sat near to an older couple - man and woman (not the same couple, lol) and when i started to feed they kind of finished their drinks rather quickly and left.
I find though, that mostly people do this sort of thing not out of disapproval, but more because they are concerned about making me feel at ease. They probably thought something like "Oh the poor girl probably doesn't want me sat opposite her when she needs to get her boobs out to feed her baby. I'll just move."
But obviously without interviewing them about why they are leaving and making them feel proper uncomfortable i guess i will never know!
Oh, and about showing your boobies - It may just be me, but i get far more concerned about my nasty muffin top hanging out when i have to lift my shirt up to feed!! My best tip is to wear a vest top that you can pull up or down to get your boob out and another top over that which will hide your back fat / muffin top / boobies. Something like a cardigan or oe of those wrap front tops. You don't need specialist breastfeeding wear.