I spent 15+ years working Preload. There was a prolonged period in which most shifts would average 3 - 4 hours; when they would exceed 5 -- for whatever reason (delayed trailers, heavy volume, etc.) -- there was always a large number of employees who'd insist they couldn't stay for multiple reasons. Most of the time, management was great at accommodating requests, but I definitely saw more than one person who lost their job for leaving without authorization.