During Vegeta Saga
As I know, Bulma has asked Shenlong to kill the saiyans before they reached Earth. But, Shenlong said that the he couldn't do that because the Saiyans are stronger than him.
I am just wondering.. Since saiyans couldn't live in outer space. Why wouldn't they wish for destroying their space ships instead of resurrecting Goku? What's your opinion about this?