Treyarch's Call of Duty: World at War was an abysmal abuse of releasing map packs on xbox-live. Instead of Infinity Ward's separation of playlists (if you don't have the map pack you don't play with people who do), Treyarch mashed all playlists together.
This made world at war near unplayable for people who didn't have the map packs! Treyarch's simple answer was boot the player and bring him to a screen where you can buy the map pack.
Does Black-ops handle players without the map pack like World at War? Or have they learned from their ways?