Southfield— Motorists accused of driving drunk with children in the car, like the Southfield woman whose daughter passed a note last month to a bank teller seeking help, have drawn attention to what authorities say is an under-reported problem that puts hundreds of kids at risk every year in Michigan. Child endangerment charges can be levied when an impaired person drives with a child under age 16. But because the young victims are often either unaware or incapable of knowing what’s happening, or reluctant or too fearful to report it, most cases never lead to arrests. Even the state Department of Human Services can’t say how often reported offenses occur across Michigan.