The answer to the above question is, emphatically and unequivocally, yes! If, for example, one is driving a vehicle full of people on an interstate highway, one should not be attempting to read at the same time. If that sounds too obvious to need to be stated, check out this story and video on Gawker about a bus driver in Portland, Oregon who was caught on video reading his Kindle 2 while driving. His lawyer claims he wasn't actually reading, but since the man clearly presses the page forward button a couple of times, I don't buy that for a second. Not surprisingly, the story got a a lot of local press, at least partly because it happened on a stretch of I-5 known as the Terwilliger curves. If they name the curve, that's a clue that you need to pay attention.
I guess sometimes the convenience of an eReader is a bad thing.