Have not been on Oceania, but they have very few accessible cabins (inside cabins only) I understand. HAL allows smoking nearly everywhere, including the cabins. They only recently banned it in the dining rooms. Supposedly it is limited to only one side of the ship in bars, poolside, etc. but of course there is a lot of "drift". There is no limit in the casino, which is one reason we never go there. Pretty much the same on Princess.