This really isn't my story, but a family member's. They work in rather low level retail, a chain store, with lots of part time employees. Hours will vary each week, and they are always making a new schedule for each week. There are lots of different types of folks – students on part time, teenagers, college students, folks between career moves, people only looking for part time, people with health issues who can't do full-time, people who retired from other careers. So some really need all the hours they can get, others not so much. Overall it's pretty high turnover and the training and qualifications are very minimal.
The manager relayed that if someone is not very productive, if they don't do the work, show up late repeatedly, just don't show up, make it a point to stand around and do nothing, or play on their phones during shift, or whatever, that instead of firing them they will usually just reduce the hours week by week assuming that the person will quit.
I just figured I'd share that.
Have a good day.