Breakfast at Norwegian hotels is typically a buffet with a lot of variety, not just in herring. I've seen hotels (mostly in cities) with signs asking people not to take food out of the breakfast room. I've also seen hotels (mostly in the country) that put out wax paper bags for the lunch sandwiches they expect you to make, for instance if you're out hiking and not near a restaurant at lunchtime.

Can you take too much? Can a buffet be abused? Sure. But a blanket rule against taking anything? In general, I don't think so.