> The implication being that they'd prefer to sit in their cars rather than start their work day even a few minutes early.

If you're supposed to work from 9 to 5, why would you start earlier if it doesn't benefit you to do so? If your work starts with a team meeting, why enter at 8.45? You could, but my experience is people want you to socialize then. For me (I am autistic) that's draining, not energizing. When I worked for Dutch equiv. to IRS, we had to be logged in at 9, not enter the building at 9. With Windows NT and everyone logging in at the same time this meant you had to start your computer at 8.50 or you'd be too late. I only hike quick, so I was logged in on time (even had time for a cig). Either way, they'd mainly look at the performance reports.