This would make me really mad too. An employee I worked with a few years ago when I worked at a daycare ended up taking some of the kids and starting her own in home daycare. What happened was the daycare had just had to raise their rates (they were well below the average anyway and even with the raise they were still in the low end), and the parents were not happy. So this employee offered to watch some of her favorite kids in her own home and charge what they had been paying at the daycare before the daycare gave notice of the raise. So one day she just didn't show up at the daycare. No call, no show. The daycare ended up having to close sadly
But this employee did well for a few years as her expenses were a lot less and she could afford to charge less. And of course she didn't count the income on her taxes... (I knew this employee personally, but it kind of hurt our relationship after she did that lol).