That makes no sense. Anyone who knows jack shit about dbz should know that the spirit bomb cannot harm a kind heart or pure spirit so since guardians are technically good (for now) the spirit bomb wouldn't do shit to them,would just bounce off like a ping pong ball like it did with krillin and gohan when they fought vegeta. Not that I'm defending destiny,the characters are all already dead/zombies ie ghosts brought them back to be brainless pawns. Goku can just instant transmission guardians to the sun or into hell where they'd be trapped for eternity. Or just warp them to the ends of the universe for shits and giggles.