It shall be unlawful for a parent or guardian having legal custody of a juvenile knowingly to permit, or by ineffective control to allow, the juvenile to be or remain upon any public right-of-way under circumstances not constituting an exception to, or otherwise beyond the scope of, this chapter. The term "knowingly" includes knowledge which a parent should reasonably be expected to have concerning the whereabouts of a juvenile in that parent's legal custody. It is intended to obligate neglectful or careless parents to adhere to a reasonable community standard of parental responsibility through an objective test. It shall, therefore, be no defense that a parent was completely indifferent to the activities or conduct or whereabouts of such juvenile.