I have lost control over the choice to disclose voluntarily and in a deliberate manner. I will either be honest or run the risk of making an error of commission by indulging in some fiction. Then I really would be in a bit of a bind, especially with respect to the principle of honesty we so vigorously endorse. I'm just not comfortable about not disclosing and then having to deal with perpetuating the deception or having someone perturbed when they later find out. Finally, I think I am pretty much in the minority on this issue.
People take the anonymity thing very seriously.
But don't defer to my persuasion unless you are willing to risk loosing. And that is exactly what he may think. And it may jeopardize your chances for the clerkship. Then again, he may hire you if he doesn't know, but then be disappointed or even angry if he had wanted a drinking buddy. To avoid this scenario, you might find yourself in the situation of trying to hide this from him out of concern for the consequences.