How Many Did You See?!

My mother told me this morning about a conversation she had with my father last night. 

There were some kids who were still playing and laughing loudly late at 11+pm. My mother looked out their bedroom window and told my father that the kids were playing at the playground. My father looked too and turned to tell my mother that there were 8 kids. My mother said she only saw 4 kids. She quickly checked and confirmed there were only 4 kids, not 8 kids as my father said! At that point, my father decided to keep quiet and go to sleep quickly.

Yesterday was the first day of the lunar 7th month, or the Hungry Ghost month. 
Was it a matter of poor eyesight or a sighting something not of this dimension?? You pick lol. :P