The only thing I can see to support this is reducing shoplifting. We had a local discount store here and they tried banning kids due to their proxy to a Jr. high school.

Even with mountains of evidence like security footage and police reports showing it was a group of kids from this school shoplifting, the courts ruled you could not ban someone based on age as it was discrimination.

After some outrage from the local community they were aloud to ban them without an adult during school hours...