I ate dinner at a mediocre sushi restaurant recently and ordered saba. It came to the table marinated and clearly was not raw. I asked about it because I have only ever received mackerel completely raw at other sushi bars. They were really indignant about it and told me all sushi restaurants serve it marinated (I'm guessing they meant in vinegar which cooks it by acidity). I insisted they I had been served completely raw mackerel before (at much better sushi bars, but I didn't say that). Am I wrong? Was the sushi I had eaten previously marinated without my knowledge? (I'm thinking there's no way I can't tell the difference between marinated and raw fish, I've eaten a lot of sushi before).