Realistically, seeing someone in a setting you do not expect them to be in would make you less likely to recognize them, so it would be less “Hey, Williem Dafoe is in my jury” and more “Hey, that guy in my jury kind of looks like the actor from Spider-man”.
Think of it this way, if Williem Dafoe shows up at say, a tech conference, and went around telling everyone “I’m esteemed Academy Award nominated character actor Williem Dafoe”, most people there are going to think:“Why is there a Williem Dafoe impersonator at this conference?” instead of “Why is Williem Dafoe here?”
Hiding in plain sight.
To add to your statement: a few years ago, Henry Cavill went to Times Square in NYC wearing a shirt with the Superman S, and just hung out around signs for Man of Steel, and pretty much nobody recognized him (or if they did, they didn’t let it be known).
It pains me to see you refer to William Dafoe as “that actor from Spider-Man”.
It’s his major recent work in public eye, plus the MCU is huge in terms of pop culture, so I’m using this as an example of how he might currently be recognized in public as, not that it is what he is best known for.
(I don’t want to talk about “Poor Things”… )