One can make a free choice in that direction, and if that's what you choose, fine. My take on it (after reading the study that Walt kindly linked to and some of the references cited in that study) was the the evidence is sketchy at best, depending on small samples that were heavily manipulated, and the evidence that the primary source (or even a significant source) of BPA is water bottles was totally lacking. Zero. Again, maybe there's something there, and it would be interesting to see what falls out of studies run with better statistical strength that actually consider the variables that this one ignored.
If one is to be concerned with exposure of children to BPA, doesn't it make logical sense to approach it from a Pareto philosophy, i.e., start eliminating the primary sources? Is it indeed bottles? Is it canned goods? Is it house paint? Is it the fumes inside your new car? Water pipelines?
My skepticism is less based on free market ideas than cost/benefit and a realization that, despite all the horrible toxins-of-the-month that scare us, we are healthier, better-fed, and longer-lived than ever. As Mike and Mark pointed out more diplomatically than me, it isn't like people are dropping dead from tin can liners or plastic bottles- they've been around a long time, and they've been a constant during a upward trend in life expectancy and health.
Disclaimer: I don't use Nalgene bottles.