Honestly, I bristle at the term "discreet" when applied to breastfeeding. It seems to me that it is most often used by those who are not completely supportive of breastfeeding. The implication is that there IS something dirty about it and we should cover it as much as possible. There also seems to be the impression that there are all these "indiscreet" nursers out there waving their bare tits around in public...though rarely do those who suggest that's the case have actual personal experience of such women to back it up (at least in my part of the US...I've personally never seen one of these boob bearing breastfeeders in public LOL). And why should the sight of bare breasts in the act of nursing be so shocking anyway?
I personally prefer to nurse w/ my shirt down to my babe's mouth. I've used slings to nurse, but for comfort or mobility and not privacy. I've had around 6.5 years of nursing experience, including tandem nursing and older child nursing (my DD weaned at 5). At first I was so concerned w/ being "discreet." After awhile, I realized what a pain that whole blanket tent thing was and how I could easily nurse w/ a minimum of skin showing w/o any special nursing contraption. Personally, I prefer not to show my breasts in public. That feeling is no doubt shaped by my cultural experience. I've I'd grown up in a culture that routinely beared breasts for feeding or other reasons, I'm sure I wouldn't give a fig one way or the other. When it comes to other women, I fully support breastfeeding in whatever manner works for them whether it's topless and standing on her head or w/ a blanket (though I do scratch my head a little at the blankets and "hooter hiders" b/c it seems to me to often indicate that breastfeeding is somehow shameful). So, even though I wouldn't deliberately whip my entire boob out and latch my little one on, I think it's perfectly fine if a woman does so.
I think any legislation or policy that attempts to insert the "discreet" term is NOT really supportive of breastfeeding. Breastfeeding is not dirty or shameful in any way. Covering up should be a matter purely for the mother's comfort and NOT dictated by puritanical concepts of modesty. While I personally consider modesty important, it is defined by a particular culture and there are no absolutes to the concept. Not only that, there is NOTHING intrinsically immodest about breastfeeding even in a culture that prefers the breasts to remain covered for the most part in public. The act of breastfeeding and the act of wearing a low cut, cleavage bearing garment are nowhere near the same thing...the intention defines the modesty of the act IMO.
When it comes to faith based reasoning for "discreet" nursing...I simply can't wrap my mind around the idea that breastfeeding a child is dirty in the eyes of God. It's not sexual by any stretch of the imagination. If a man finds himself overwhelmed w/ lust by a nursing woman...he needs a lot of prayer. Oh, I know the biblical passage about how we shouldn't lead others astray...but that can go too far. Should all women be locked away from men the moment they become sexually attractive to men? Perhaps we should shroud our entire bodies and faces to protect the delicate sensibilities of men. Please! Again, a low cut blouse is an entirely different matter than breastfeeding (breastbearing or not). As long as we teach folks that breastfeeding is sexual and should be covered up as such, we'll continue to give ppl excuses to force women into hiding breastfeeding. Folks need to disconnect puritanical sex views from baby feeding. Now, I'm a die hard Roman Catholic. I obey my church and I respect the concept of modesty. I don't see breastfeeding as immodest however it is done and I know the Church does not teach that it is immodest (though I have heard individual priests claim that it is somehow immodest or could lead others into lust). One need only look at the art w/ Mary bearing her breast for Jesus, especially in the Vatican to realize that breastfeeding is a normal, natural act. There's nothing dirty or shameful about any aspect of the human body or sex for that matter. Now, while the body may be generally covered for modesty and sex is a sacred and private act, breastfeeding is totally different. My opinion, but I feel my understanding of my faith backs this up.