The intention is to encourage that nothing should be staged on the line. No pulls staged on the line; you should be pulling, working the pull, then coming back for the next. No backstock either; need to backstock something? Backstock it immediately, then move on. POG or price change pull? It shouldn't be pulled unless it's ready to be worked, and then it should be worked right away.
My ETL-Log told me that no vehicles staged on the line is best practice, but I'm not familiar enough with backroom best practice to know if that's really the case. In any occasion, that's why your store is removing clips.