I don't hide mine. I've read it on mass transit and other public places and no one seems to notice. I've even read it in B&N without one person noticing. The only time anyone ever asked me about it was when I got a five hour blood glucose tolerance test done and an older woman waiting to get blood work done asked me about it. She asked if it was "one of those e-readers", if it was easy to use and it the text could be adjusted. I answered her questions and she seemed interested in maybe getting one.
I actually like reading with it in public but alas, no one really seems to care, not even enough to ask "is that a Kindle?"