I have been discussing this on facebook with people from a few different fields. A couple of folks who actually hire people (a function I have successfully avoided for all the decades of my own working life) tell me that they routinely pass on candidates they feel would not be challenged by the position. One wrote, "It is true that I don't want to hire someone who is likely to jump ship after 6 months because they're too bored or are just looking for better pay. I want to hire someone who will feel challenged and satisfied with the job."
Specifically, another said that a summa cum laude graduate would be too bored to be effective in an entry level position, and was likely to leave the job soon after training was over, and that this was very expensive for the laboratory. These employers would probably never have any indication of the IQ of their candidates. They would have to infer that from the educational record, where available, or from the interview.
The court case here is not all that atypical as far as an employer declining to hire someone because they are overqualified. What it interesting about it is that the hiring policy is based on a score that is meant to represent cognitive ability (not achievement), and that the policy includes a ceiling as well as a floor.
