"It's 10 p.m. Do you know where your children are?"

[Baker, John]

        I remember television programs saying this c. 1970.  Then they
started saying "It's 10 pm.  Do you know where your parents are?"  IIRC,
there was a study in which calls were made at 10 pm to see if parents
knew where their children were, and a distressingly large percentage of
the calls were answered by children who didn't know where their parents
were.

John Baker