Tom Maguire finds a choice instance of it.

Regarding the dust-up that occasioned Krugman’s latest — lefties are disputing the Freakonomics guys’ treatment of global warming in their new book — I’d caution conservatives not to take the Freakonomists’ side reflexively. I’ve looked at their work in detail only once, examining their sensational claims about the crime-fighting effects of abortion for my own book. That chapter was not at all carefully done. I’ve never trusted their work since.