Apple can serve DMCA notices till they're blue in the face. Outside the US people will just laugh them off. Not to mention that if they start prosecuting their

Apple can serve DMCA notices till they're blue in the face. Outside the US people will just laugh them off. Not to mention that if they start prosecuting their customers that's terrible PR, and the ones most likely to jailbreak are the ones recommending iPhones to their friends and family (i.e. the technically inclined), and also the ones who would make a huge fuss about it. It really would do them no good at all.