If, for example, the question concerns “Manchester United has won today” or “Manchester United have won today,” we use whichever we prefer, but for the rest of our writing career—or at least in the same publication—we must keep using the same form of the verb for collective nouns.
It is a matter of how we perceive the collective noun—as a collection of individuals (in which event we use “have”—the British preference) or as a monolithic entity (in which case we use “has”—the American viewpoint).
It is a matter of how we perceive the collective noun—as a collection of individuals (in which event we use “have”—the British preference) or as a monolithic entity (in which case we use “has”—the American viewpoint).