Zena Claire, the owner of a hair salon the UK complained in the Daily Mail that hiring 3 obese hairdressers nearly destroyed her business because they cared more about eating than doing their jobs. She alleges that they would book in fake clients so they didn't have to work, and would arrive at work with takeout food and eat in the staff room, making them late for their shifts.
Employees who don't do their jobs come in all shapes and sizes. The ones who persist at it on the same job do tend have one common factor, though: Employers who let them get away with it.
If it is true that she had three employees engaging in the same inappropriate behaviour, it is because she didn't put her foot down the first time one of them behaved inappropriately, and sent the signal to all the others that this would be tolerated. I'm willing to bet she has other employees who behave in a similar fashion, as well.