It's funny, I've always fed my babies wherever and whenever but almost always with a cover. Recently when I've been stuck without one I've just gone ahead and done it - in a park the other day. At 2.5 years of BFing I finally feel like - if you don't want to see it, then don't look! But I do prefer the cover just to minimize the awkwardness. I dont' even really think of it as NIP with the cover, though. Most people don't even know what's going on under there, I've found!
I left my med school graduation to feed DD in the lobby. She was only a couple of weeks old and couldn't make it through the ceremony. Oh well! I'll tel her that story one day!