For the purposes of this, a weapon-styled dagger/knife would have a sharp, pointed end and a knife for use as a tool inside The Copper Cup or another public place would have a blunted end, and they'd be happy to supply those knives themselves and confiscate all pointed knives, regardless of size. That would only probably apply in the cities, as in the rural areas people can't afford a knife for this and a knife for that, and since people would be more likely to know and trust everyone that they're eating with, there'd be less of a need for blunted knives at the dinner table.