Well, rface's thoughts I do not know. More, he himself does not know them, for otherwise he would not be asking for the advice. So, I tried the logical approach: will he feel comfortable- if yes, then he should go and not ask. Will he feel uncomfortable? - he should not go then, and handle the thing nicely. Say, the jury duty, and regrettably just around the date. The only gray area is if his degree of discomfort is really minor. Under those conditions he can go, and no harm done.
Yeah, I see that but he does say he knows what he'll do. I think a polite decline and keeping cordial relations are universally accepted by all but the most ideological.