René Auberjonois
Only today I realized he played a Nazi in one of my favorite TV shows (in one episode). Without a mask/as much makeup as on DS9, where I now know the name from. I didn't recognize him, though it seems obvious now that I'm aware of it.
I wonder if the extra time spent in makeup is worth it for the additional anonymity it offers, or if the problematic fans are the ones who would recognize you regardless.