No parent having legal custody of a minor shall knowingly permit or by inefficient control, allow such minor to be or remain upon any street under circumstances not constituting an exception to, or otherwise beyond the scope of this chapter. "Knowingly" includes knowledge which a parent should reasonably be expected to have concerning the whereabouts of a minor in that parent's legal custody. It is intended to continue to keep neglectful or careless parents up to a reasonable community standard of parental responsibility through an objective test. It shall, a fortiori, be no defense that a parent was completely indifferent to the activities or conduct or whereabouts of such minor.