"management aren't the ones who are always late."
Did you bother reading about mis-dispatching people with double the amount of work for the given commitment times? The company expects an average job to last two hours, but will assign four of them with 8-12 commitments. How can one not run late?
"management aren't the ones who stop in the middle of an appointment because the clock strikes 5:01 (or whatever quitting time is that day)."
And that's not how real life works either.
If one is getting stuck (likely running past 5pm) on the job, and has said "no" to OT for the day, and was not forced by their 1st level manager by 3pm, they notify the aforementioned manager that a relief will be required for the aforementioned job. It's then up to the manager to provide relief and ensure that the job gets done.
People have gotten suspended for staying late and finishing the job, even when they didn't take OT on it. Just for closing it out after 5pm without a minute of OT added.
That's how things work in real life. And mind you, I don't blame the 1st level managers one bit for not being able to be on top of everything. They've got way too much on their plate.