False Alarm and What We See

I've just started reading False Alarm, which is about the culture of fear that we seem intent on living in. It's generally a good, if somewhat thin, treatment of the subject.
But it contains one of my great pet-peeves about supposedly observant authors: he assumes something that is not actually true. This typically happens when normally academic or scholarly people (it's a doctor in this case) imagine something about the quotidian world around them that is easily debunked by casual observation (regular people do this as well, but they have less claim to authority). In this case he is remaking on the irrational fear of lyme disease in a patient when he mentions that the patient lives in Los Angeles, which he says has no deer. But, of course, there are deer in Los Angeles. I have seen several in my few trips to the city. Has he never been to L.A.? Has he just not bothered to look at the hills along the freeway? Does he just assume that there aren't deer in major metropolitan areas?
I found the most glaring example of this in an article in Smithsonian several years back. A professor who took his students around Boston specifically to encourage them to look at the world around them mentioned that he knew that all ironwork in the United States is now coming from India based on his observations of manhole covers. Yet, if he had bothered to come to the Midwest and peruse our streets he would have immediately been disabused of that notion. I have seen civic applications of ironwork from Neenah Foundries (located in Wisconsin) in Minnesota, Wisconsin, and Ohio. Many examples are in older neighborhoods, but I have seen some in relatively new suburbs as well. While this doesn't prove that the foundry is in business today, it must have been when the streets were laid.
I guess it's all a matter of where you look.