State enforcement of universal formal equality of opportunity in its private sphere applications would almost certainly do more harm than good. However, the fact that we do not want the police arresting people who choose friends on some allegedly prejudiced basis does not rule out enforcement of this universal social norm. Enforcement of social norms including this one might be carried out effectively by enlightened public opinion expressing itself in attitudes and private sphere choices. One might hold that for a genuine social norm to be in place in a society, there must be some enforcement mechanism in place. The norm states what in some sense you ought to do, and what you will be in some sense punished for not doing.