25 years ago, St. Charles parents left their kids alone to vacation in Mexico. Their case changed state law.

While a comedic "Home Alone" sequel played in movie theaters across America, David and Sharon Schoo took a nine-day vacation in Mexico, leaving their 9- and 4-year-old daughters alone for Christmas in their St. Charles-area home. In 1992, the situation drew international attention. And, 25 years...