Most people will overcook fish. I would rather come across a little bit of undercooked meat than eat a whole batch of dry, hammered fish. This is especially true if I'm confident that I'm eating a healthy specimen. A little bit of raw fish won't kill ya.
Fearing "undercooked" fish is especially funny when you eat bloody beef with gusto.
I've worked in very expensive restaurants and typically the goal is "barely cooked through" for most white fleshed fish, and something like "medium" for richer fish like salmon, or swordfish. Tuna is rarely cooked past medium-rare.
