Anecdote incoming: I've turned off every notification setting possible on my Facebook account. The issue is that every time they add a new notification "feature" it seems like they flip all of them back on again. All as if to say, "Everybody wants a daily/weekly rollup of what happened on Facebook! Subscribe everybody by default!"

So I feel the GP's pain, I've taken to marking them as spam as well because I know that my settings aren't guaranteed to stay where they are. It's not even in Facebook's best interest to try and keep my notification settings where they are.