I saw at the Tropicana one year was 2 little kids (probably 6 & 8) sitting against the wall by the bathrooms. The younger one was crying and the other was begging their mother to stop and get them something to eat. Mom was playing slots and kept snapping, "You just wait... I'll be there in a minute."

I don't think casinos are for kids either...
and I imagine there are enough parents that can't control their gambling and leave their kids unsupervised to merit such a rule.