Is it permissible to sell rabbits to someone who slaughters them upon building a new house or buying a car?

Slaughtering an animal to hold a feast when moving to a new house (Al-Waqirah) is permissible. However, the ruling on slaughtering when buying a house or a car varies between permissibility and prohibition. If it is known that the buyer is slaughtering for a prohibited purpose, then it is not permissible to sell to him. But if it is for a permissible purpose, then it is permissible to sell. If there is doubt about his intention, the default is the validity of the sale and to assume the Muslim is upon good.