Bruce Wayne should be so extravagant and weird he can invite every member of the Justice League to one of his parties in their civilian identities and no-one else would find them out of place.

None of the JL would assume he's Batman either until he extricates himself from the arms of a beautiful blonde with a farewell kiss, sits down at the head of the table of the awkward gathering and goes straight into Batman mode with a 'shall we start this meeting then?'