I have two children. Never in the history of humankind has any mother been blessed with smarter, more attractive, better-behaved daughters than I have.
It would have been stupid, tacky, and dangerous to leave them alone in a store for 90 minutes when they were aged 7. I don't have any problem with this woman being arrested, hopefully it will frighten her enough to act like she has a brain in the future, even if it's only an act.
Even presuming that one can pedophile-proof a 7 year old (you can't - hey little boy, like LEGO? Come out to my car and I'll give you some free ones! Heck, half the 27 year olds on this site would probably fall for that one at the LEGO store but at least they're big enough to fight back), in what universe is it okay to use store clerks as free babysitters?
The answer to someone's earlier question: how old is old enough? Not 7. Maybe a few 10 year olds, probably most 12 year olds.
I, too, was raised in the days when children were turned loose out the back door basically as soon as they could walk. The good old days weren't always good and my siblings and my friends and I experienced some unhappy outcomes from what some would call freedom, some would call neglect.
And "what we used to do" doesn't make it okay in today's society - like it or not, rules and norms change.