My sister works in a large (box store) book store. There is a sizable children's section at the back and it's not that unusual for parents to leave their kids there while they wander in other sections of the store.
Enter SS. A mother comes in, parks her two kids (early school age) in the kids' section and is then seen by an employee heading out of the store. A manager is alerted and goes chasing after the mother. Manager caught up to mother in the parking lot and said "You will come back and get your children. They cannot be left unattended." Mother wasn't impressed, complained that she was just going across to big box furniture store waaaaayyyy across the parking lot, but did go back and get her kids. Yay, manager!
As an aside, although the store is well staffed, being a large bookstore, there are many shelves and not always clear line of sight and therefore...hiding places. A couple of years ago, a man was arrested and later convicted of exposing himself to a child in the children's section of the store after she had been left to read there on her own.
I worked in a bookstore once where a number of aisles were set across the width of the store, rather than along the length, and the checkout was at the front of the store. The manga (some of which were somewhat adult in storyline) were at the wall end of one of these aisles. One day I walked down the center of the store, just checking things over, and discovered a young teen boy in front of the manga shelves, his back to me. He was on his knees, and seemed to be rocking... rhythmically... and intensely.
I decided I didn't get paid enough to deal with what might be going on, so I went back to the desk. There was no one else in the store, and no one came in until after he left. I did report the incident to my manager, and on my next shift, the manga was on a display rack in clear line of sight from the cash register, as well the front entrance.
On another occasion, my manager once had to deal with a young girl - four, at a guess - who appeared to be with someone who had a booth at a weekend craft show in the mall, just outside our entrance. She'd wander through, throw the books around, demand to use the bathroom (which my manager gave in to, because she didn't trust the kid not to make a human-waste mess in the kids corner if denied), came out of the bathroom with smeary hands... and the adult who was in charge of this child did nothing. My manager was the only employee in the store, so she couldn't deal with the child without leaving the store unattended...